GARDEN DOCTORS: Succulents that can survive freeze
Published: Saturday, February 2, 2013 at 4:02 a.m.
Last Modified: Saturday, February 2, 2013 at 11:02 a.m.
Howard writes: This latest cold snap has caused my new succulents (that I planted last summer in containers) to become literally mush!
The temperatures in areas of my garden where the succulents were located got down to 27 degrees Fahrenheit.
My questions are: Are there any succulents that can tolerate colder temperatures? What can I do in the future to protect the plants from freeze damage? Also, can you suggest any additional growing tips that would be helpful? I am not ready to give up on the "succulent challenge" (my description) this soon.
I had a discussion with Charolett Baron, a knowledgeable succulent and cacti hobbyist, and asked her how her succulent collection has fared during our unusually low temperatures.
Also, she shared some of her hard-learned succulent growing experiences when she too lost some favorite specimens during a previous cycle of hard-freezing temperatures.
Here are some of her recommendations for selecting succulents that are more tolerant of cold temperatures and what she does to protect her succulent and cacti collection:
She has found that the yucca, 'Wall Bright Star' is hardy to 0 degrees and the agave, 'After Glow' is more cold tolerant. Baron found these specimens at Cottage Gardens in Petaluma.
Variegated specimens seem to be less hardy. Euphorbias do not tolerate frost. Container plants are more sensitive to lower temperatures even though they are considered hardy to, say, 30 degrees.
Crassula sarcocaulis is cold tolerant to 10 degrees. Sempervivums, commonly referred to as hens and chicks, tolerate cold temperatures. Sedums, also known as stonecrops, come through the cold temps with no apparent damage.
Baron recommends covering ALL your succulents with frost-protectant material that breathes and allows moisture and sunlight to penetrate.
Lightweight sheets draped over the plant during the cold temperatures also work well but need to be removed during the day.
Move the containers under eaves or other protected areas. Hold back on the water until the weather warms up.
If you have a mini-greenhouse or something larger, run some low-voltage lights for additional warmth and continue to lightly cover the pots with frost protectant material, also called floating row covers, until no longer needed.
Lastly, her own succulents have survived because she covered those in containers, those planted in the ground and even those in her greenhouse.
In my own garden, the sedums, sempervivums, Orostachys, Senecio mandraliscae, Crassula cocinea 'Campfire', Rhodiela and Aloe nobilis were not damaged when the temperatures went down to 28 degrees.
When purchasing succulents, read the plant label and it will usually tell you the cold-hardiness of the plant. Within a particular genus, some may be hardier than others.
The number of days of low temperatures will also affect the hardiness as well as a prolonged rainy period such as we experienced.
Those readers living in a warmer microclimate will have success growing the slightly more tender succulent varieties.
Interestingly enough, visiting neighbors in your area that have experienced little to no plant frost damage will also help you determine what succulents will thrive in your own garden.
A terrific reference book for all succulent enthusiasts is "Succulent Container Gardens, Design Eye-Catching Displays with 350 Easy-Care Plants" by Debra Lee Baldwin.
This book answers a multitude of questions covering cultural requirement of succulents, individual plant hardiness and enticing container arrangements using color, texture and size that complement each container.
Cynthia asks, what are the physical characteristics of a yucca compared to an agave?
Yuccas are 2 to 3 feet tall, mounding succulents with spiky foliage that have stringy hairs along their edges. They bear flowers on stalks in early or mid-summer.
Agaves also have a clumping growth habit; their leaves are about 18 inches long and 3 inches wide with sharp spiny tips. Agaves, also known as century plants, rarely produce flowers, but when they do they are on stalks that reach several feet above the foliage clump.
Both of the plants are cold tolerant.
Jess S. writes: Is it OK to graft a citrus onto a camellia? Don't want to remove the camellia's root system if it isn't necessary.
No. The camellia and the citrus are not compatible.
(Send your gardening questions to The Garden Doctors at email@example.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.)
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