This is late but I thought I'd chime in for anyone curious about this in the future. The purple tree collards I grow rarely go to seed in our SF Bay Area climate. However, last year in our region just about every purple tree collard plant I knew of produced a few seeds. This year I haven't seen any purple ones flowering, but I know of several people in the central valley whose plants are flowering. There must be some kind of weather/regional condition that triggers flowering.
Their seeds are not known to come reliably true. However, they are certainly viable. They will produce a range of progeny, some of which will be similar to the mother plant, and some more reminiscent of other leafy cole crops. It is similar to planting the seed of an apple tree... you don't know if you're going to get a delicious vigorous apple variety, but it will definitely be an apple. Occasionally a seedling will produce something worth propagating. The purple tree collard itself was at one point a seedling from some cross...
So, I recommend growing some plants from cuttings or already rooted plants if you are able to get ahold of them. The purple tree collard plant is an amazing perennial vegetable. We actually began selling purple tree collard plants
a year ago because they were so hard to find elsewhere.
We have also been collecting and trialing other more obscure varieties of tree collards. We have so far tried two varieties that we have since decided aren't worth sharing- one marketed as a 'white' tree collard, and another was a seedling of a purple tree collard which then was propagated by cuttings. Both went to seed heavily and had much less vigor that the purple tree collards we grow.
We have however come across some varieties which are worth sharing. One is a cross between a dinosaur (lacinato) kale plant and a tree collard saved by a local backyard gardener. It is named the Dino tree collard
. It goes to seed each year heavily but rebounds with impressive vigor as opposed to other kale plants which tend to slow down after their first year. It is possible that a future breeding program could result in a plant with similar characteristics but with less tendency to flower.
We also discovered a plant at a local community college where they had let loads of brassicas go to flower and reseed all over the place. It is named a "Merritt Collard"
. It is more bushy than a typical tree collard but produces enormous leaves: up to 2+' and 1/2 a lb. in weight. It also goes to seed annually but has a vigorous growth response in the following months. They are flowering in our garden right now.
It would be great to get a cross of the dino collard and Merritt collards which had the size and vigor of the Merritt Collard, but had the ruffled slightly more tender leaves of the dino collard plants...
In a few weeks I am going to go visit my friend in the central valley whose plants flowered this year. We hope to be offering limited quantities of his purple tree collard seeds
later this year. For people outside of the U.S. this is currently the only way of getting tree collards. They should also be of value to plant breeders. We shipped this guy in Australia seeds last year and he has gotten a variety of interesting seedlings
Hope this is of value.