Is Eucomis Winter Hardy?

Considering the increased production of Eucomis as both a cut flower and potted plant crop, we wondered about the winter hardiness of this southern Africa native.

We received bulbs which had originated from Eddie Welsh, well known to ASCFG members as a premier breeder of Eucomis varieties. In midsummer 2012, we planted 10-15 bulbs of three cultivars. They had been grown in six-inch pots in the greenhouse for growth regulator trials by Jack DeGoede of DeGoede Bulb Farm and Gardens in Mossyrock, Washington.

After we collected our research data, the flower stems were cut off, and bulbs were planted in perennial trial beds at our Bluegrass Lane trial site in Ithaca. The site has very well-drained loamy soil (rare for our immediate region but much appreciated!), and after planting, the area was mulched with two inches of double-ground hardwood mulch. No further mulch, winter protection, fertilizer, or special care was given other than an occasional irrigation if needed.

The plants emerged in late spring 2013, grew slowly through early summer, and were beautiful and healthy in mid-July (photo right). Flowering began in early August, with the white cultivar ‘Innocence’ being a bit later than the other cultivars.

Since we did not anticipate any survival, we really did not keep accurate records on the number of plants used, etc. But it is clear from the plots and photos that the plants were substantially hardy this past winter, and did not suffer any extensive winter damage. Leaves were excellent (no burned leaf tips, distorted growth, etc.) and more importantly, the flowers were flawless. Quite a surprise.

But is this a new and novel finding? The website of the Pacific Bulb Society states: “In cultivation they have proved to be hardy to frost, especially if planted deeply or protected during their dormancy by snow” (http://www.pacificbulbsociety.org/pbswiki/index.php/Eucomis). While interesting, the term “frost” is ambiguous (much used in England and mainly irrelevant to really cold areas!) and “frost plus snow” in many areas of the western United States is invariably a milder degree of cold than what we see in normal upstate New York winters.

So…is Eucomis winter hardy? First, we had only a limited selection of varieties originating from one breeding program in New Zealand. Eddie Welsh tells us these are E. comosa types, so perhaps we can tentatively assume that other E. comosa cultivars might show the same degree of winter hardiness. We have no way of knowing about other eucomis species or cultivars without additional trialing. As well, this represents only one winter. We will leave the plants in place and observe for the next several winters. If they continue to thrive for another couple of winters, then we can be quite sure that these plants will deserve much wider landscape use (and as a perennial cut flower, perhaps in tunnels or in open ground plots) in the future.

As an aside, check out the agapanthus in the first photo on the next page.  This is ‘Back in Black’, and it has come through three winters. We have a number of other cultivars (‘Dr. Brouwer’, ‘Triumphator’, ‘Elisabeth’, ‘Pinocchio’ and a lovely unknown dark blue cultivar that was mislabeled as ‘Polar Ice’) come through two winters so far, and are getting bigger and stronger each year. A white cultivar, ‘Sea Foam’, has thrived in our trials for 11 years!  These are all small-flowered types and not the giant large cultivars.

Trust us, we do not have a lock on climate change in Ithaca, but just pointing out that plants can’t read, and in the right place (well-drained soil being essential, as winter wetness is usually to blame for marginally hardy plants failing in the winter), many plants will do better than expected. For the record, Ithaca previously was in the cold end of zone 5 (zone 5a), and now resides in zone 5b with the winter hardiness revision from 2012. (http://planthardiness.ars.usda.gov/PHZMWeb/).

Eucomis plot in mid-July. Note also the Agapanthus ('Back in Black') in the background; it has survived three winters.
Eucomis in mid-August, having overwintered in the ground the winter of 2012-2013 in Ithaca, N.Y.

Bill Miller

Bill Miller is Professor of Horticulture at Cornell University. Contact him at [email protected]

Chris Wien

Professor

Chris Wien is recently retired Professor of Horticulture at Cornell University. Contact him at [email protected]