The purple tree collard is a vegetable gardener’s dream. With a little attention every now and then a tree collard plant will provide you with delicious, nutritious greens all year round. Here are some basics to get you started.
Perennial member of the brassica family, hardy to around 20° F
The tree collard is a member of the brassica family. It is related to traditional collards, kale, broccoli, cabbage, brussels sprouts and a number of other popular vegetables. However, unlike most of its relatives, purple tree collards are perennial. This means that, like a fruit tree or rose bush, once you plant them they will continue to grow and produce year after year. Traditional collards, kale, etc. must be grown from seed each year and then die after they go to seed. This is one of the top reasons why so many people love tree collards- once you have a plant established you don’t have to plant new seeds every year.
Tree collards are hardy to around 20° F. In fact, they taste best after a frost. If they are exposed to temperatures below 20° for an extended period of time, your plants will die and you will have to start new ones. Thus, tree collards are especially suited to mild climates, such as those on the pacific and southern coasts of the United States. Some people in colder climates still manage to grow tree collards by taking them indoors each year.
New plants are easily started from cuttings
Starting a new tree collard plant is simple. Instead of seed, you will need a cutting from the branch of another tree collard. We have a complete tutorial on how to propagate tree collards from cuttings here. Occasionally tree collards will bloom and set some seed (unlike many other vegetables, tree collards will keep growing and thriving after they have set seed). These seeds can be grown but they won’t make a plant identical to the mother plant. You can certainly grow seeds as an experiment- you may wind up with another new type of leafy green- but the tried and true method of propagating tree collards is via cuttings.
Tree collards can grow upwards of eight feet tall
Take some time considering where to plant your tree collards in your garden. If planted in fertile soil they can grow over eight feet tall! Tree collards are a great way to create privacy in your garden. At the end of our video on planting tree collards there are some examples of staking them and training a collard up an arbor.
Tree collards, like most vegetables, thrive in moist, well aerated soil rich in organic matter. In drought conditions, tree collards respond by producing smaller leaves and growing slower. If you want large plants with a big harvest, you will need to make sure they get supplemental irrigation during dry periods. However, they can live a surprisingly long time with minimal water.
Pruning and Harvest
Tree collards require very little maintenance once established. If they are left to do there own thing though, they will tend to develop long, leggy stalks that are unattractive and less productive. To create bushier, more compact growth, it is important to prune them on occasion. We have a tutorial on pruning and harvesting here.
In Northern California where we grow our tree collards, they are virtually pest and disease free. When our broccoli and kale are getting hit by aphids, the tree collards are often unscathed. Our tree collards are also less affected by slugs and snails. Each year during the summer they do get a bit of powdery mildew on older leaves. We pick these off and compost them or feed them to our poultry. Deer love tree collards, so it is important to plant them in protected areas! Please help us improve this section by sharing your experiences with pest and diseases on our Facebook page.