We’ve been growing these for 20 years and they are still our favorite variety of tree collard. When most people talk about tree collards, this is usually the one they are talking about. Purple Tree Collards produce all year long and taste especially good in colder weather. They turn darker purple tones in Winter and are lighter blue-green in warm months. Purple Tree Collards rarely go to flower and seed. Purple Tree Collards can be grown multi-trunked and kept as low as 3 feet tall or as tall as 12 feet. If grown with a single trunk, it will need a strong support and will be quite woody and bare down low. For this reason, we prefer to tip prune Purple Tree Collard plants to keep them bushy and productive. Purple Tree Collards are sometimes called Taunton Deane kale in Great Britain but it appears to be essentially the same plant.
Purple Tree Collards
Merritt Tree Collard
This plant is from a chance cross at a local community college. They are a vigorous tree collard with large leaves measuring over 2 ft’ and weighing over 1/2 pound. Merritt Tree Collards have a round dense shape when young and eventually grow up to 7 feet tall after 5 years. They do often go to seed in spring but they are still productive in the flowering/seed pod phase. Merritt Tree Collards can be propagated from thinner cuttings or very thick stalks by cutting them with a saw and placing them in a large pot with high quality potting soil. You can also save seed and come up with interesting hybrids if you have other brassicas blooming at the same time. These seedlings tend to have sturdy, thick stalks, and to be more climate adapted than the mother plant. They grow well in USDA zones 11-8, and marginally in zones 7a and 7b. Some of the seedlings have been reported to survive New England winters without protection.
Green Tree Collards
These are grown the same as Purple Tree Collards, but they seem to max out at 5-6 feet and are green with light green ribs. They seed heavily in mid Spring and are less productive during that time. Let them flower and set seed before you cut them back. They taste milder than purple tree collards and look more like traditional collard greens.
Dino Tree Kale/Collards
Dinosaur Tree Kale/Collards
These are from a seedling grown by Rebecca Newburn, whose Purple Tree Collards flowered at the same time as her Lacinato (dino) kale and she saved the seeds and grew them out. At the time, this was her favorite of the seedlings. It looks somewhat like a lacinato kale plant, but grows more or less like a small tree collard. The main drawback is that it flowers vigorously each spring, which slows down leaf production. You can eat these flower shoots like small broccoli. Once they have flowered and set some seed you can cut back the flower stalks and the plants will resume leaf production.They have a milder taste than Purple Tree Collards. Dinosaur Tree Collards are a smaller, less vigorous tree collard that is naturally multi-trunked and grows to 3-5 feet maximum.
Daubenton Kale (Variegated Perennial Kale)
This in an edible and ornamental perennial kale that grows to a nice compact 2-3’ bush and doesn’t get leggy and woody like tree collards can. You can plant them in your garden and many people won’t even know that they are an edible plant. We prefer the productivity and vigor of Purple Tree Collards if you want to maximize production, but these are a great ornamental edible. Our plants have not bloomed in the 10 years we have grown them. In our experience these plants are much more difficult and slow to propagate than the other varieties, but our fellow plant propagators in the UK have an easier time.
Jolly Green Tree Collard
Jolly Green Tree Collard is a 2020 introduction and extremely limited perennial tree collard. It is a naturally occurring garden hybrid from the Berkeley Farm that appears to be a cross between the Merritt Tree Collard, Green Tree Collard, and maybe even Purple Tree Collard. It gets between 6 and 10 feet in height, and appears to naturally branch into a large shrub form. Within the first year or two, it forms a 1 inch diameter trunk.
Once Jolly Green reaches 2-3 feet in height, it is best tied to a sturdy, metal stake as it can get top heavy in storms and high winds. Leaves can get up to 2 feet long and are a bright to medium green color with lighter stems. They are smooth like annual collards, but much larger. It doesn’t not appear to be a big bloomer which means it is much more productive through the spring than some other tree collards. Because it is a new introduction, at this time its cold hardiness and heat tolerance is unknown. Based on past experience, it should be at least as cold and heat tolerant as its parentage. One can expect it to be good in zones 8-11, and probably marginal in zones 7A and 7B.
Big Blue Tree Collard
Big Blue Tree Collards are a 2020 introduction and extremely limited perennial tree collard. It is a naturally occurring garden hybrid from the Berkeley Farm that appears to be a cross between the Merritt Tree Collard, Dino Tree Collard, and maybe even Purple Tree Collard. Big Blue gets between 3 and 8 feet in height, and appears to naturally branch into a mid-sized shrub form. Within the first year or two, wide stalks 1-2 inches in diameter can form.
Once Big Blue reaches 2-3 feet in height, it would be best tied to a sturdy stake as it can be top heavy in storms and high winds. Leaves can get up to 1 1/2 feet long and are a stunning blue-green color with a hint of pink/purple in the stems. They are crinkly like Dino Tree Collards, but much wider and less linear. Because it is a new introduction, at this time its cold hardiness and heat tolerance is unknown. Based on past experience, it should be at least as cold and heat tolerant as its parentage. One can expect it to be good in zones 8-11, and probably marginal in zones 7A and 7B.
Michigan Tree Collard
Ken Asmus of Oikos Tree Crops shared clones of his Michigan Tree Collard with Project Tree Collard. This hardy tree collard came from a plant that has been outside for the last 5 years in USDA zone 5-6, and has survived temperatures to 0 F. Michigan Tree Collard is a vigorous, silvery colored tree collard that has purple hues on the stems and new growth. Flavor is similar to other tree collard plants. It may be tolerant of even colder winter temperatures than zero, and even if it appears to have died above ground, it re sprouts from below the soil line once the growing season resumes. Some have hardy enough stems to stay green and sprout slightly above the ground. It grows up to 6 feet tall, and if given fertile, well-drained soil with regular water can reach 3-4 feet high in one year.