Thursday, December 27, 2018

Post Holiday bulb care

by Irene Shonle, revisiting an old favorite
The holidays are winding down and many of us now have pots of withering Amaryllis and paperwhites.  While it’s harder than I consider worth it to get paperwhites to re-bloom again in our climate (they are not hardy for planting outdoors), don't throw out your Amaryllis.  With a little care, it can bloom again next year - even better than it did this year!

Spent Amaryllis & Paperwhites
 The secret is to keep the plant actively growing after it blooms to recharge the bulb; it takes a lot of energy to produce such big flowers. If the bulb does not produce a flowering stalk the next blooming period, it is likely that has not stored enough nutrients during the post-blooming period.

After the flowers have faded, cut the flowers off to prevent seed set. Only cut the flowering stalk after it turns yellow, a green stalk continues to produce energy for the bulb.  In order to feed the bulb for next year's show, water and feed the plant regularly with an all-purpose houseplant fertilizer. Put the plant in the sunniest possible location for the rest of the winter to encourage strong leaf development. I have found that putting the pot outside during the summer after all danger of frost helps maximize photosynthesis and gives the best results. Make sure to slowly acclimate the plant to full sun to avoid sunburn (gradually increase the time spent in the sun each day for about a week).  I have also noticed that critters don't seem to bother either the leaves or the bulb - a bonus around here.  Remember to feed the plant a few times during the summer in addition to regularly watering.

Red Amaryllis
For blooms in time for the holidays, stop watering in mid-August and bring the pot inside. Let the foliage die back naturally as the soil dries out completely. When the leaves have withered, store the dormant bulb in a cool, dark and dry place for a minimum of eight to twelve weeks. Then, about six to eight weeks before you want the Amaryllis to flower again, place it in bright light and begin watering again - sparingly at first, so the bulb is not sitting in water.

If you don’t care when it blooms, there is no need to do the fall dormancy protocol. Continue watering and fertilizing the plant, and bring it inside before frost. Keep it in a sunny window, and it will usually bloom sometime in spring. The flowering stalk should emerge with or before the leaves if you have taken proper care of the plant. Watch as the number of flowers on the stalk increases in both number and size as the bulb increases in size.  Over time, the bulb may produce a new bulb, which you can remove and pot up separately. Amaryllis plants bloom best when they are somewhat pot-bound (crowded roots). They require re-potting only every 3 or 4 years. The best time to re-pot them is after they have gone through a dormant period in the fall.
Paperwhites in Winter
Irene is the County Extension Director in Gilpin County

Monday, December 17, 2018

Poinsettias and plants that may, or may not be, poisonous

by Kurt M. Jones
While Poinsettia plants are not actually poisonous, I was recently asked about this.  As a concerned parent of two young children, I decided to do some research about poisonous plants, and learned that the toddler in my life is more harmful to my Poinsettia houseplant than the plant is to him.
Poinsettia, not poisonous

However, this is not true of all plants in our home and landscape.  Some plants that grow in our landscape or surrounding areas can be dangerous for our children and pets.  One website that I often visit when looking into poisonous plants is CSU's Guide to Poisonous Plants,  This is a searchable website written by Dr. Tony Knight, DVM from the CSU Veterinary School.  Dr. Knight is a world-recognized expert on plant toxins for animals, but he cross references many of his plants as affecting humans.

Upon visiting the site and searching for 'humans,' a list of 22 plants was returned.  This site has good color pictures of plants, animals affected, and geographic locations of these plants.  Of course, there are many plants we are not likely to plant in our landscapes (like leafy spurge, water hemlock, death camas, or buckeyes). Yet, there are some plants that may find their way into our landscapes or potted plants (like Oleander, Autumn crocus, Glory lily, Rhododendron, Delphinium and Daffodils) that are toxic.  Easter lilies are especially toxic to house cats.
Easter lily
I also visited the Cornell University website for toxic plants, and did a search for plants poisonous to humans.  About 55 plants were returned in this search (including several mushroom species).  Included in this list is the Poinsettia, which was surprising.  The Society of American Florists has given a 'Clean Bill of Health' to the Poinsettia plant. It is, however, wise to keep Poinsettias and other plants out of the reach of children and household pets that show a desire to chew or eat plants.  The white latex sap in the leaves and stems is mildly irritating to the mucous membranes of the mouth, and for some animals it will induce excessive salivation and vomiting if plant parts are swallowed. The wide variety of hybrid poinsettias available today have very little toxicity compared to the parent species.  Other Euphorbia’s, include the various spurges, have been shown to be hazardous to humans when handled or consumed.
Leafy spurge

I also researched the incidence of plant poisonings for this article and was surprised at some of the findings.  According to the American Association of Poison Control Centers, there were 64,236 (2.7 %) cases involving plants.  In pediatrics (age 5 or less), the percentage is higher (3.7%).  Of the plant calls received by poison control centers involved in this report, the Poinsettia was number 2 on the list.  For more information, visit their website at  Should you suspect poisoning, call 1-800-222-1222.  If it is an emergency, of course, dial 911.

So what should you do to prevent unwanted poisonings?  First, keep plants out of the reach of children.  Babies and toddlers like to stick new items into their mouths, and plants parts may be a choking hazard even if they are not poisonous.  Learn to identify problematic plants in and around your home.  Do some research on potential plant additions before bringing them home and endangering children or pets.  Should you have poisonous plants in your landscape or home, consider removing or take steps to insure they cannot harm (i.e. fencing off or elevating them in your home).
Kurt Jones is the CSU Chaffee County Extension Director

Monday, December 10, 2018

Great reference book for insects and diseases of woody plants

by Kristina Hughes
Gardening in the mountains is full of challenges, so I am always looking for reliable sources of horticultural information pertinent to our region and our specific issues (like this blog!). And it is especially important to have good information when trying to figure out what’s wrong with a struggling plant.

For the past two seasons I have been volunteering at the Jeffco Diagnostic Clinic where people bring us their sick plants for diagnosis. They also bring us insects they suspect might be doing evil in their landscapes, mysterious fungi that have appeared unbidden (often in mulch), and unfamiliar plants about whose identity clients are simply curious. We have to solve all kinds of garden and landscape problems.

We have an entire library of resource materials at the Clinic, including compendia of turf diseases and vegetable diseases, books large and small on almost every plant pathology subject. But I have found that there one which is my favorite. I don’t leave home without it (literally - I keep a copy in my car at all times). It’s easy to use and easy to understand. It’s geared specifically to problems in Colorado. I’ve been known to read it in my spare time because it’s so well organized and has such good pictures.....

It is ‘Insects and Diseases of Woody Plants in Colorado’ from CSU Extension, 2014 edition. It is a soft-cover, spiral-bound book of 322 pages and it cost $40 when I bought my copy several years ago.

It’s easier to use than any of the other books because in the back near the index there is a excellent key which directs the reader to the most likely culprits for any given plant.

Have you ever wondered why Ponderosa pines drop the tips of their branches periodically? If you looked in the back of this book, under ‘Pines’ there is a subsection for ‘Affecting trunk and larger branches’ and then a listing for ‘Chewing off twigs’ which directs you to read about Abert's squirrels on page 259. There you will find pictures of the types of damage squirrels can do to trees along with detailed information about which plants they damage, times of year damage is most likely to occur, life cycle of squirrels and recommendations for management. It is just enough detail for a layperson to be able to identify the problem and execute a solution confidently, without getting lost in overly technical jargon.

Spruce Gall Photo by Kristina
Have you seen this on a spruce? 

Or this on an aspen?
Poplar Twiggall Fly Photo by Utah State Extension

With this book, it’s easy to find out that the first one is Cooley Spruce Gall (page 140) and its mostly a cosmetic issue which usually doesn’t require intervention. The second one is caused by Poplar Twiggall Fly (page 141)which also doesn’t do much damage to the plant. 

This book addresses only problems of woody plants. But our woody plants are long-lived, important foundational elements in our landscapes and their loss can be devastating. This book contains a very broad range of information on insects, larger animal pests, bacteria, fungi, as well as non-living causes of disease, all organized in a highly accessible manner, which makes it easier for us to help our plants when they are struggling. I wish there were more books like this for other types of plants.

We have so many challenges in the mountains and having correct information allows us to be more effective when dealing with those challenges. I have found this book to be incredibly useful both in my personal gardening and in my various Master Gardener roles. It’s also just fun to read!

Kristina Hughes
Clear Creek County Master Gardener