Category Archives: House plants

Meet the Garden Squad—Gardening Help at the Denver Botanic Gardens

Meet the Garden Squad is a way to get better acquainted with some of our CSU Extension Master Gardener volunteers.

Meet the Gardening Help Volunteers

The CSU Extension Master Gardeners usually pick up the gardening helpline at the Denver Botanic Gardens or answer questions when people walk-in the door. Even though buildings at DBG are closed for now, gardeners can still get their gardening questions answered by Gardening Help from Colorado Master Gardeners at Denver Botanic Gardens, only remotely.

The interest in gardening has soared ever since people have had to hunker down at home and find ways to keep busy. First-time gardeners will likely have questions on how to get started, what to plant now, what can grow in containers, and much more.

Even gardeners with some experience have questions, too. All gardening questions can be emailed to gardeninghelp@botanicgardens.org and a CMG, working remotely, will reply by email.

Gardening Help volunteers include: Back row, left to right: Jan Fahs, Jan Davis, Ken Zwenger, Mark Zammuto, Gordon Carruth, Fran Hogan
Middle row: Lynne Conroy, Harriet Palmer Willis, Kathleen Schroeder, Leona Berger, Cindy Hanna, Mary Adams, Nancy Downs
Kneeling: Dee Becker, Charlotte Aycrigg, Jan Moran
Not pictured: Mary Carnegie, Linda Hanna, Maggie Haskett, April Montgomery, Ann Moore, Kathy Roth, Amy White

Gardening Help is a project of the CSU Extension-Denver Master Gardeners at the DBG. Volunteers provide reliable and research-based information to thousands of home gardeners each year.

Volunteers commit to at least one year in the role, with a minimum of six shifts spread across the year. The commitment starts early in the year with an orientation and training from Nancy Downs, project coordinator.

Many volunteers are GH regulars and they return to the project every year. In addition to being an active CMG, they have to satisfy DBG volunteer requirements, too. That means they’re a member of the DBG and enrolled there as a volunteer.

Some of the key characteristics of GH volunteers are good research, plant identification and diagnostic skills. Because the project is located at DBG, volunteers need to keep on top of what’s blooming at the DBG by season, so they can answer common questions that might pop up.

Photo provided by Nancy Downs

Text by Jodi Torpey
Master Gardener volunteer since 2005

Poinsettia Challenge – Steps for Reblooming

plant-185709_1280It’s January and the holidays are behind us, but if you can’t bring yourself to toss your poinsettia plant, why not try to coax it into reblooming next December? It takes basic indoor plant care skills, perseverance and some properly timed steps to insure flowering.  Here are season-by-season instructions for success.

Winter: Protect the plant from cold and drafts, with daytime temperatures of 67-70 degrees, nighttime temperatures of 60-62 degrees. To maintain healthy foliage, fertilize monthly following balanced houseplant fertilizer directions, water when the soil is dry below the surface but not soggy.  Avoid “wet feet” by draining excess water from the plant saucer.

Watch for mealy bugs (cottony puffs), which can be easily removed with a cotton swab dipped in rubbing alcohol.

ec001cosSpring: By late March or early April the plant will look tired – it’ll most likely have dried, yellowed or fallen leaves. You’ll be tempted to put the plant out of its misery at this point!Instead, remove the bracts and part of the stem, ideally leaving 3-4 leaves on each stem. This pruning can be done anytime through mid-July.

Late spring/early summer: Repot the plant in a pot that is one size larger (approximately 1-2” inch larger in diameter). Use a quality, well-drained potting mixture, fortified with 1 tablespoon super phosphate (0-46-0) per gallon of soil mix. Slow-release fertilizer applied to the soil surface is also beneficial if the soil mix does not already include fertilizer.

Summer: When outdoor temperatures are consistently above 60 degrees, the plant can live outdoors in a shaded area such as a porch.

It will be putting on a lot of growth during this time and should be pruned about every six weeks to promote side branching and good form. Stop pruning in late August.

Late Summer: If the plant has been outdoors, you’ll want to bring it in around Labor Day or when nighttime temperatures drop below 55 degrees. Place it in a sunny or bright location with temperatures of 65-75 degrees. Continue monthly fertilizing.

ec002cosFall: Poinsettias require 8-10 weeks of shortened days to stimulate flowering. Starting the first week of October, put the plant in complete darkness for about 15 hours a day -ideally 5pm-8am.

It can be covered with a big box, put in a closet or sequestered in a room with no light at all.  Longer, completely dark nights and bright, shorter days are the key to successful reblooming. This step is non-negotiable.

Around Thanksgiving, colored bracts should appear. This is the sign to stop the dark treatment, continue fertilizing to promote blooms and keep in a warm, bright spot in your home and enjoy your holiday plant!

I have a big, beautiful poinsettia, have set my calendar reminders and am ready to give this a try.  How bout you?

Additional reading:

https://extension.colostate.edu/topic-areas/yard-garden/poinsettias-7-412/

https://extension.unh.edu/resource/poinsettias-care-and-reflowering-fact-sheet

Photo: Pixabay.com

Drawings: Colorado State University

Written by Linda McDonnell, a Denver County Master Gardener

Test Your Poinsettia IQ

poinsettia-458762_960_720Poinsettias (Euphorbia pulcherrima) are making their December debut this week. With up to 50 million plants sold annually, you are likely to give,  receive, or at the very least, encounter the plant in your daily travels this holiday season.

How much do you know about the care and history of this botanical holiday plant?

True or False? Poinsettias are highly poisonous – keep children and pets away.

Mostly false. According to the University of Illinois Extension, “A study at Ohio State University showed that a 50-pound child would have to eat more than a pound-and-a-quarter of Poinsettia leaves (500 to 600 leaves) to have any side effects. The leaves are reportedly not very tasty, so it’s highly unlikely that kids or even pets would be able to eat that many!” So, while ingestion can cause mild stomach irritation the plant is not considered highly toxic.

True or False?  The plant was brought to the U.S. in 1915 by a shopkeeper as a gift for parents who brought their children to breakfast with Santa.

False. Robert Pointset, a botanist, physician and first U.S. Ambassador to Mexico is credited with bringing the plant to the U.S. in 1848, when they were introduced at the Philadelphia Flower Show.

True or False? For longest enjoyment, select plants with tight oval bead-shaped structures, which are the actual flowers that surround the colored leaves or bracts.

True. The colored bracts, or modified leaves (commonly, but incorrectly referred to as the flower) will start to fade when the center cyathia  (flower) open and release pollen. Look for tight, spikey bead-shaped buds when selecting plants.

True or False? The Aztecs used the colorful parts of the Poinsettia to make a reddish-purple dye for clothing and believed the sap cured fevers.

True. Poinsettias were used for practical and ethnobotanical uses in ancient cultures, including coloring cloth and treating fevers.

True or False:  National Poinsettia day is October 1st, the day that plants should start receiving 12-14 hours of complete darkness in order to rebloom. 

Partially true. October 1st is the date to start giving your Poinsettia half days of complete darkness, called photoperiodism, to trigger reblooming.  But if you want to celebrate Poinsettia day (and who doesn’t?)  it is December 12th, the day Robert Poinsett died in 1851.

True or False: Poinsettias come in over 100 natural colors. 

True. Local garden centers have lots of red, pink, cream and coral varieties along with some sassy lime green, orangey-yellow cultivars and splotchy multi-colored bracts.  Mother Nature has no hand in producing the Bronco blue and sparkly grape colored varieties – these are sprayed and glittered.  There’s a poinsettia for every taste!

True or False: Allow a Poinsettia in bloom to dry out completely before watering.  

False. Poinsettias can be divas — water when soil surface is just dry to the touch so check daily, especially if the plant is in a small pot.  Leaves will droop and yellow if the plant gets too dry. Don’t let the plant sit in water and keep it away from cold and drafts. Ideal temperature is between 65-70 degrees and there is no need to fertilize when in bloom.

Which is the correct pronunciation Poin-set-ah  or Poin-set-ee-ah?

Either way is correct!

Check back next month for tips on coaxing your poinsettia to bloom next year. It’s a good challenge for indoor plant collectors.

Written by Linda McDonnell, a Denver County Master Gardener
Photo courtesy of Pixabay,  a source for royalty free photography

 

No More Buds? Turn to Earbuds.

By this time in the year, I’m at the point of good riddance! with the weeds and careful tending (shout out to this cold spell for sealing the deal). Pretty much everything is done and put to bed. I then spend the next two weeks really dialing into my houseplant game before I get bored and start Spring dreaming. My Fall break from the garden is short-lived so I start listening to old episodes of now-defunct podcast series and dream with new ones.  Here are a few of my favs:

Gardenerd Tip of The Week

Gardenerd.com is the ultimate resource for garden nerds. We provide organic gardening information whenever you need it, helping you turn land, public space, and containers into a more satisfying and productive garden that is capable of producing better-tasting and healthier food.

https://gardenerd.com/

My thoughts: The host lives in LA, so this one is great for winter listening as we get chillier, I love hearing about the warmth of Southern California and what’s coming into season. Interviews with other experts and educators in the horticulture field discussing plants, but also cultivating grains, discussing bees, and seeds. Each episode ends with the guest’s own tips, many of which are news to me and have been incorporated into my own practices. 

On the Ledge

I’m Jane Perrone, and I’ve been growing houseplants since I was a child, caring for cacti in my bedroom and growing a grapefruit from seed; filling a fishtank full of fittonias and bringing African violets back from the dead.

https://www.janeperrone.com/on-the-ledge

Houseplants, if new to the podcast start here for an overview, and guidance.

Jane is a freelance journalist and presenter on gardening topics. Her podcast has a ton of tips for beginners, and more advanced info for longtime houseplant lovers, as well as interviews with other plant experts. The website is also useful to explore the content of an episode if you aren’t able to listen. I could spend an entire morning traveling in and out of the archives. 

My thoughts: As the growing season comes to a close, my indoors watering schedule starts wobbling between what the plants need and my summer habits of watering too many times per week–welcome back,  fungus gnats! Here’s an entire episode on them

Plant Daddy Podcast

We aim to create a listener community around houseplants, to learn things, teach things, share conversations with experts, professionals in the horticulture industry, and amateur hobbyists like ourselves. We also want to bring the conversation beyond plants, since anybody with leaf babies has a multitude of intersectional identities. We, ourselves, are a couple gay guys living in Seattle, Washington, with a passion for gardening and houseplants. A lot of our friends are the same, though each of us has a different connection, interest, and set of skills in this hobby, demonstrating a small amount of the diversity we want to highlight among plant enthusiasts.

https://plantdaddypodcast.com/

My thoughts: Plants are visual, podcasts are auditory- episodic overviews with links to viewable content available on their website. Are you also seeing Staghorn Ferns everywhere? They have an entire episode (photos included!) on the fern and how to properly mount it for that vegan taxiderm look. Matthew and Stephen are self-identified hobbyists with a passion for plants all the way down to the Latin–it’s impressive.

Epic Gardening

The Epic Gardening podcast…where your gardening questions are answered daily! The goal of this podcast is to give you a little boost of gardening wisdom in under 10 minutes a day. I cover a wide range of topics, from pest prevention, to hydroponics, to plant care guides…as long as it has something to do with gardening, I’ll talk about it on the show!

https://www.epicgardening.com/

My thoughts: The Netflix-episode-when-you-just-don’t-feel-like-a-movie kind of podcast. Addresses the best varietals, composting, soil pH, and troubleshooting some common issues in the garden. With daily episodes archived back to December 2018, there is a quickly digested thought for some of your own curiosities. The website is also a wealth of knowledge. 

Eatweeds Podcast: For People Who Love Plants

Eatweeds: An audio journey through the wonderful wild world of plants. Episodes cover modern and ancient ways wild plants have been used in human culture as food, medicine and utilitarian uses.

http://eatweeds.libsyn.com/

My thoughts: most recent episode (and appropriately timed!)  On edible acorns. My fav topics include foraging and wild yeast fermentation; and when I really start missing the Pacific Northwest, The Wild and Wonderful World of Fungi sends me back to a misty forest wander politely decorated by les champignons. Posting of this pod is sporadic–only 25 episodes since 2014.

You Bet Your Garden

(no longer on air, but archives available)

 

You Bet Your Garden® was a weekly radio show and podcast produced at WHYY through September, 2018. The show’s archive is available online. It was a weekly syndicated radio show, with lots of call-ins. This weekly call-in program offers ‘fiercely organic’ advice to gardeners far and wide.

https://www.wlvt.org/television/you-bet-your-garden/

My thoughts: Host, Mike McGrath, spends much of the show taking calls and troubleshooting, reminiscent of another public radio behemoth with Click and Clack, the Tappet brothers. McGrath incorporates a lifetime of organic gardening tips with humor. McGrath features one tip to find a local “rent a goat place” (no joke) to get goats to eat the most troublesome weeds to a concerned caller considering setting much of her yard on fire.

Cultivating Place: Conversations on Natural History and the Human Impulse to Garden

Jennifer Jewell, the founder of Jewellgarden and Cultivating Place, achieves this mission through her writing, photographs, exhibits about and advocacy for gardens & natural history and through her weekly public radio program and podcast Cultivating Place: Conversations on Natural History and the Human Impulse to Garden, on gardens as integral to our natural and cultural literacy.

https://www.cultivatingplace.com/

My thoughts: sort of like On Being, but for gardening.

A fav episode:

If you aren’t so sure about this podcast thing, and just want a place to start, start here.

Do you really need a brain to sense the world around you? To remember? Or even learn? Well, it depends on who you ask. Jad and Robert, they are split on this one. Today, Robert drags Jad along on a parade for the surprising feats of brainless plants. Along with a home-inspection duo, a science writer, and some enterprising scientists at Princeton University, we dig into the work of evolutionary ecologist Monica Gagliano, who turns our brain-centered worldview on its head through a series of clever experiments that show plants doing things we never would’ve imagined. Can Robert get Jad to join the march?

https://www.wnycstudios.org/podcasts/radiolab/articles/smarty-plants

Help Your Christmas Cactus Bloom This Year

cropped-cropped-dscn05311.jpgWe’re sharing this post from 2016 again as a reminder that dark, cooler autumn nights are needed for Christmas Cactus to produce glorious blooms at the holidays. Given the right conditions now, you’ll enjoy beautiful flowers before too long. Read on for all the details!

Let me start by saying I’ve killed my share of houseplants, but one that has lived for close to three decades is the Zygocactus. Commercially, growers sell two slightly different plants as Zygocactus: the Thanksgiving cactus which has pointy edged branch segments and blooms around turkey time and the Christmas cactus which has rounded segments and blooms for its namesake. Care for the plants is essentially the same. Mine, shown above, is the Thanksgiving variety, Schlumbergera truncate.  Through periods of  neglect, inconsistent feeding and infrequent (twice maybe?) repotting, this plant keeps blooming prolifically year after year. I’ve rooted cuttings several times as gifts, but curiously, the offspring have rarely flowered in their new homes, where I might add, they get more TLC than they would living with me. This begs the question, what does this plant need to thrive and re-bloom? Here are the best tips from the experts and a few of my own observations.

  • It likes a bright, but not sunny location with temperatures that do not drop below 60 degrees.  Mine moves from indoors to an east facing screened porch from Memorial Day till Labor Day, or longer if the fall is mild like it was this year.
  •  It is a cactus which likes humidity. Unlike most cactus which prefer dry air, it hails from the tropical rainforests of South America and likes moist air. Sitting the plant on a pebble tray with water that does not touch the bottom of the pot can help, or living in a kitchen or bathroom would be ideal.
  •  It wants good drainage. If repotting, use standard, well draining potting soil. Water when it is dry just below the soil line, about once a week. I’ve  found  it amazingly forgiving if  when I forget to water. Over-watering will cause branches to rot, so more is not always better.
  • Spring and Summer are its active growth times. Prune when it is done blooming or in early summer to promote side branching. Cuttings can easily be rooted in water or soil. Adding houseplant food during the growth period helps. I have cut back branches to about six inches in the spring and the plant tripled in size by the end of the summer.
  • Here’s the key! It needs longer autumn nights to rebloom. Photoperiodism is a plant’s reaction to periods of light, similar to our circadian rhythm. Starting in mid to late September, the Zygocactus needs between nine and twelve hours of uninterrupted darkness each day in order to flower. Thanksgiving cactus take about six weeks of longer nights to sprout buds, Christmas cactus need about eight to twelve weeks.  This longer “sleep” period is the trickiest part of the reblooming process and why the porch, which is generally dark at night, works so well. Other options are to locate the plant in a similarly lit room, or  early each evening, cover it with a box or put it in a closet. Complete darkness insures maximum blooms. From experience, I’ve found that the occasional interruption of darkness reduces blooms, but will not thwart all flowers.
  • Stop the longer night process when buds emerge. The plant is now ready to flower. At this time, reduce watering slightly to promote brighter flower color.
  • Watch for bud drop. This could indicate you’ve reduced water too much. If the plant is new to you, it also could be reacting to a change in environment. Drafts or temperatures below 60 degrees may also be the culprit. I often see shriveled tiny buds at the end of the blooming cycle, as though the plant is  exhausted from the work it takes to flower for weeks on end. I found no science to support this notion, just my take on it!

Zygocactus are graceful, pretty plants, with or without blooms. Their showy, colorful holiday flowers are a beautiful treat at the end of the year. With a little extra care in the fall, they will regale you with splendid  holiday color.

Related posts:

Keeping the Ho Ho Ho in Holiday Plants

A Year in the Life of an Amaryllis

Text and Photo by Linda McDonnell, a Denver County Master Gardener

Indoor Plants & Clean Air

 

Over thirty years ago, NASA began researching methods of air purification in space crafts to pave the way for long-term human space flight. The study, found here, concluded that many common houseplants are highly effective at removing toxins such as benzene, formaldehyde, ammonia, xylene and trichloroethylene. The findings have been replicated many times over. Their relevance today is unmistakable, especially given the number of man-made products which off-gas chemicals in our homes and workplaces, current energy-efficient construction practices, our focus on healthy living and concern for the environment.

The following are answers to commonly asked questions about the relationship between clean air and indoor plants.

How exactly do plants clean the air?

Plants are effective at absorbing gases through pores on the surface of their leaves. It’s this skill that facilitates photosynthesis, the process by which plants take in carbon dioxide and release oxygen. In effect, all plants can purify the air to some extent, but some do a better job than others.

Studies show that plants can absorb many gases, including a long list of volatile organic compounds (VOCs). Benzene (found in some plastics, cloth and pesticides) and formaldehyde (found in some cosmetics, dish detergent, fabric softener and carpet cleaner) are common indoor VOCs that plants help eliminate.

Plant roots and the microorganisms that live in healthy soil also absorb VOCs and other pollutants.

Which plants were used in the NASA study?

Most were common, easy to care for plants which you may have in your home or office right now. Top “air filters” included: Peace lily (Spathiphyllum wallisii), golden pothos (Scindapsus aures), mother in law’s tongue (Sansevieria trifasciata ‘Laurentii’), bamboo palm (Chamaedorea sefritzii), dracaena (Dracaena marginata), spider plant (Chlorophytum comosum), English ivy (Hedera helix), Chinese evergreen (Aglaonema commutatum). Gerbera daisies (Gerbera jamesonii) and potted mums (Chrysantheium morifolium) are also effective air purifiers, but tend to be short-lived flowering houseplants.

Can plants reduce the harmful effects of cigarette smoke in the air?

Cigarettes contain formaldehyde, one of the toxins that plants can remove from the air. However, the plant/cigarette smoke connection was not the focus of the NASA study. A 2010 study by the American Society of Horticulture Science found that ferns were among the most effective plants in formaldehyde removal.  Check out the study for specifics on which ferns offer the best results.

Do I need to live in an indoor jungle to reap benefits?

Hardly! Studies found that approximately one 6″ to 8″ pot per 100 square feet, or 15-18 plants per 1800 square foot house makes a measurable difference.  The more vigorous the plant, the more pollutants it will draw from the air.

 

Photo credits: Bing free images

Written by: Linda McDonnell, a Denver County Master Gardener

 

 

 

 

 

Shedding Light on Houseplants

20160201_134705

Daylight saving time is on hiatus, the gardening season has drawn to a close and  the long shadows of winter will soon be here.  It seems like a good time to turn our attention to the light needs of indoor plants.

Most indoor plants hail from the tropics, making their ideal growing conditions far different from what we offer in our typical homes. Thin new leaves, loss of lots of older foliage and limbs stretching towards a window can all be signs that your plant is craving more light. Without adequate light plants are unable to store energy for growth.

Indoor light is more subtle than the light in our gardens, which can make it trickier to assess. For more precision, a photographer’s light meter or a simple light meter app on your phone will measure the light in foot-candles or LUX units. Horticulturists use foot-candles, so if you have a device which gives a LUX reading, search the web for an easy LUX to foot-candle calculator.

In general, growers characterize plants as needing high, medium or low light.  Here are some guidelines to help assess the type of light in your environment with greater accuracy.

High Intensity Light

  • 1,000+ foot-candles
  • 4-6 hours of sun per day
  • Crisp shadows and dark contrast at the brightest time of day
  • Within 2’ of east facing windows
  • Within 2’ of south-facing windows (October-March)

Medium Intensity Light

  • 500+-1,000 foot-candles
  • Within 2’ of north facing windows (April-September)
  • 2-6’ from an east or west-facing window
  • 1’ to the side of an east or west-facing window
  • Approximately 10-14 hours per day of fluorescent office light

Low Intensity Light

  • 50-500 foot-candles
  • Faint shadows at the brightest time of day
  • Within 2’ of north facing windows (October-March)
  • 6-10’ from south-facing windows (April – September)
  • Few plants survive in fewer than 50 candles

Knowing the light intensity will help determine the best placement of  plants and select  plants which will thrive. Variables such as humidity, drafts and temperature also factor into a plant’s health, so be sure to take this into consideration, too.  As always, knowledge and keen observation skills are key to successful plant care.

Additional information on plants and light:

Plantalk 1352: Interior Plants and Light

Plantalk 1314: Houseplants: Artificial Light

Starting Seeds Indoors

Christmas Cactus Care (effects of light on bloom)

 

Written by Linda McDonnell, a Denver County Master Gardener

 

 

 

 

A Poison Plant Primer for Halloween

While on a garden tour a few years ago, I crossed over to the dark side. Instead of admiring the frilly flowering ornamental plants, I spent my time inside the Poison Plant garden. 

The gate, decorated with a large iron spider in a large iron web, creaked eerily on opening and then slammed shut behind me.

The spider signified the potential dangers that grew inside that garden, like Oleander (a glycoside). This innocent-looking plant can cause respiratory difficulties and heart problems. Although this Mediterranean shrub can be a fragrant addition to the landscape, every part of the plant is poisonous when eaten. The smoke is also toxic if plant parts are burned.

Other glycosides in the garden included foxglove and lily-of-the valley.

Why would a perfectly nice botanic garden include harmful plants among the others? For the same reason so many other plants are on display: to educate gardeners and the general public.

We can’t escape poisonous plants because they can grow anywhere. Jimson weed and nightshade; soapwort and poison ivy; stinging nettle and even St. Johnswort were a few of the other plants growing in the garden.

“A recent increase in herbal usage has given rise to misuse and mistaken identities,” explained a sign near the poison garden’s entrance. “It is important to consider means of preventing a toxic encounter as well as enjoying the contributions of poisonous plants around us.”

Because Halloween is a time for delightful frights, I recommend taking a read through Amy Stewart’s entertaining book called “Wicked Plants: The Weed that Killed Lincoln’s Mother & Other Botanical Atrocities” (Algonquin Books of Chapel Hill, 2009).

She includes poisonous plants familiar to most gardeners, like Castor Bean, Henbane, Hemlock and Deadly Nightshade. But she also includes some surprises like Habanero Chile, Sago Palm, Tobacco, Junipers and Bermuda grass.

“We assume if it grows out of the ground, a plant is natural and natural is good for you,” says Amy. But cyanide is also a natural substance that comes from some plants, and it definitely isn’t good for you.

Speaking of deadly plants, what do you think is the world’s most wicked plant? Scroll past the following poison plant resources section to learn the answer.

Resources

A nice addition to Amy’s book is a list of poison gardens throughout the world and a well-research bibliography with many poisonous plant resources and identification guides. Here are a few links to help get you started:

CSU’s Guide to Poisonous Plants database lists trees, shrubs and perennials that can be harmful to animals.

Cornell University’s College of Agriculture and Life Sciences has a searchable database of plants that are poisonous to livestock and other animals. The color images help with plant identification.

The University of Illinois Extension has a comprehensive list of links to poisonous plant information. 

The World’s Most Wicked Plant?
Tobacco

By Jodi Torpey
Denver Master Gardener since 2005

A Year in the Life of an Amaryllis

amaryllis_akaIf your holiday amaryllis is nearing the end of its blooming cycle, here are tips to enjoy the plant through the year and give it the best chance to bloom again. Unlike paperwhites, which are one-and-done indoor bulbs, with care, amaryllis can re-bloom for years to come.

While flowering, the plant benefits from bright, indirect light and moisture. When each trumpet-shaped flower is finished, snip it off and when the last flower on the stem has shriveled, cut the entire stem about an inch above the bulb. Leave the strappy leaves in tact. Occasionally amaryllis won’t develop leaves until after blooming, so don’t fret if the plant is foliage-free at this stage. However, adding fertilizer to a bulb without leaves will kill the roots.

Treat the bulb as a houseplant throughout the winter by providing direct sunlight, watering when dry below the soil line and feeding common houseplant food once or twice a month. The bulb should remain snuggled in the original pot, with the top half to one-third above the soil line. In spring, the leaves will yellow and die, signaling that they’ve done their job of providing nutrients to the bulb, a common bulb process. Cut the foliage about an inch from the top of the bulb; new leaves will emerge through the summer. Leaves equal energy, so the more leaves developed at this time, the more vigor the bulb has to flower again. During the summer months, you’ll want to give the pot as bright a spot as possible, either indoors or out. Burying the pot in a partially shaded garden bed is also an option.

In September, reduce water significantly until leaves turn yellow and die. Store the plant in a cool, dark area (45 to 50 degrees) for 8-12 weeks, checking regularly for signs of new life and watering sparingly. This fall “Goldilocks” phase of not-too-hot, not-too-cold is critical to the forcing process so choose the resting spot carefully. When you see fresh growth, move the plant to bright light and resume regular watering. The plant is now ready to produce new foliage and flowers.

Many find this process a snap. If that’s not the case for you, keep in mind that the size and quality of the bulb can effect re-blooming, so from the start choose large, blemish-free bulbs which are heavy relative to their size. Amaryllis forced in water are also unlikely to re-bloom as they lack the energy to survive. But if this experiment doesn’t work for you, you may not want to give up as the bulb can take a year off from flowering and then come back with a vengeance. Growing amaryllis sure can be an exercise in patience!

Posted by Linda McDonnell, a Denver Master Gardener

Christmas Cactus Care

chistmas-cactus

Let me start by saying I’ve killed my share of houseplants, but one that has lived for close to three decades is the Zygocactus. Commercially, growers sell two slightly different plants as Zygocactus: the Thanksgiving cactus which has pointy edged branch segments and blooms around turkey time and the Christmas cactus which has rounded segments and blooms for its namesake. Care for the plants is essentially the same. Mine, shown above, is the Thanksgiving variety, Schlumbergera truncate.  Through periods of  neglect, inconsistent feeding and infrequent (twice maybe?) repotting, this plant keeps blooming prolifically year after year. I’ve rooted cuttings several times as gifts, but curiously, its offspring have rarely flowered in their new homes, where I might add, they get more TLC than they would living with me. This begs the question, what does this plant need to thrive and re-bloom? Here are the best tips from the experts and a few of my own observations.

  • It likes a bright, but not sunny location with temperatures that do not drop below 60 degrees.  Mine moves from indoors to an east facing screened porch from Memorial Day till Labor Day, or longer if the fall is mild like it was this year.
  •  It is a cactus which likes humidity. Unlike most cactus which prefer dry air, it hails from the tropical rainforests of South America and likes moist air. Sitting the plant on a pebble tray with water that does not touch the bottom of the pot can help, or living in a kitchen or bathroom would be ideal.
  •  It wants good drainage. If repotting, use standard, well draining potting soil. Water when it is dry just below the soil line, about once a week. I’ve  found  it amazingly forgiving if  when I forget to water. Over-watering will cause branches to rot, so more is not always better.
  • Spring and Summer are its active growth times. Prune when it is done blooming or in early summer to promote side branching. Cuttings can easily be rooted in water or soil. Adding houseplant food during the growth period helps. I have cut back branches to about six inches in the spring and the plant tripled in size by the end of the summer.
  • Here’s the key! It needs longer autumn nights to rebloom. Photoperiodism is a plant’s reaction to periods of light, similar to our circadian rhythm. Starting in mid to late September, the Zygocactus needs between nine and twelve hours of uninterrupted darkness each day in order to flower. Thanksgiving cactus take about six weeks of longer nights to sprout buds, Christmas cactus need about eight to twelve weeks.  This longer “sleep” period is the trickiest part of the reblooming process and why the porch, which is generally dark at night, works so well. Other options are to locate the plant in a similarly lit room, or  early each evening, cover it with a box or put it in a closet. Complete darkness insures maximum blooms. From experience, I’ve found that the occasional interruption of darkness reduces blooms, but will not thwart all flowers.
  • Stop the longer night process when buds emerge. The plant is now ready to flower. At this time, reduce watering slightly to promote brighter flower color.
  • Watch for bud drop. This could indicate you’ve reduced water too much. If the plant is new to you, it also could be reacting to a change in environment. Drafts or temperatures below 60 degrees may also be the culprit. I often see shriveled tiny buds at the end of the blooming cycle, as though the plant is  exhausted from the work it takes to flower for weeks on end. I found no science to support this notion, just my take on it!

Zygocactus are graceful, pretty plants, with or without blooms. Their showy, colorful holiday flowers are a beautiful treat at the end of the year. With a little extra care in the fall, they will regale you with splendid  holiday color.

By Linda McDonnell, a Denver County Master Gardener