Short version: If you like kale crisps get a purple tree collard. They seem expensive to acquire, but once you have one you get lots of food for their footprint, they’re beautiful, perennial and really easy to grow.
I have written a generic post on kales and collards before, but I think this is worth a special mention now. This is partly because it has grown into a pretty impressive, well… tree… since the last photo and also because:
- Purple tree collards are perennial
- They grow throughout the year, including winter and the hungry gap
- They taste great (and in fact get sweeter after a frost)
- They’re rather attractive with their purple colours
- The leaves get huge so that you only need a couple of leaves for a meal
- They do fine in part shade
- They do well in the alkaline clay soil that I have
- They grow really tall, so they use up the vertical space.
When I say tall. I really do mean tall. I guestimated this to be around 8 feet tall. I put a standard folding garden chair in front of it today (20/03/20) for scale.
My only gripe is that whilst being tasty, the large leaves are quite tough, so a good old stew is required. Alternatively (and this is my favourite way to eat them) they make fantastic kale crisps. Because they’re tougher they hold together much better than the other kales.
Getting a purple tree collard
They are fiendishly hard to get hold of. Because they are perennial, they don’t tend to produce seed. Even if they did produce seeds, they may have crossed with another local brassicas so you wouldn’t be certain of how the offspring would turn out. Read more about cross pollination here . They are not sold by the usual commercial vegetable providers. This means that the only way to get one would be off eBay or a specialist website like https://backyardlarder.co.uk/ (like I did) or from someone who has one. The cutting may have seemed rather small for the £7.95 price tag with delivery added on top of it. However, because of the rarity of the plant and the wonderful provider that it has become, I think it was well priced. Once you have one, creating cuttings is rather easy so in a couple of years my lawn may have been replaced by a purple tree collard forest.
How to grow
They like fertile alkaline soil so the clay soil in London is perfect. It is said that you should avoid growing annual brassicas (cabbage, kale, sprout, cauliflower type things) in the same spot year after year as they can develop club root. I’m not sure whether purple tree collard is susceptible to club root, but because the purple tree collard is perennial it can happily stay in the same spot for years. I would maybe suggest that you don’t start your purple tree collard in a spot that has had cabbages growing in it year after year. Also, as it’s going to be there a while it is worth adding lots of nutrient rich organic matter, like compost. I did some hole composting over winter before I planted the purple tree collard into this bed.
When I made this new bed, I mixed in about 2 months’ worth of kitchen waste (peelings, cores – any uncooked vegetable and fruit matter) and 2 shredded Amazon delivery boxes. I then covered it and left the worms and decomposing bacteria to do their thing for a couple of months. By the time I planted the purple tree collard in, everything had broken down nicely. There was some nice organic matter mixed in with the squidgy clay. You can see the soil in the pictures below looks darker and crumblier. The cutting was planted into the garden in February.
I’ve been taking cuttings since it was around 8 months old. A healthy side shoot with around 6 leaves is a good candidate. Cut the stem with a clean knife. Remove all the leaves except maybe the top one or two small ones. Stick into a pot of compost. You can dip the cut tip in rooting hormone if you like but it hasn’t seemed necessary. Place away from the sun and don’t let it dry out. It will take a couple of months for a good root system to grow.
The young smaller leaves can be blanched and stir fried with a little garlic and salt (or we use a pinch of chicken stock). Or it can be used in anything you would use kale in. It is sweet and slightly nutty and tastes… well … like kale.
The older leaves, and this includes the huge leaves, make great kale chips. Remove the stem and the central vein of the leaf (otherwise you get slightly soggy crisps)and chop into pieces. Toss in a mixture of a teaspoon of sunflower oil, a dash of sesame oil, a pinch of sugar and a pinch of salt (or again… chicken stock) before laying on a grill tray in a single layer. Roast at 1800C for about 7 mins or until crispy and slightly brown at the edges.
I was quite surprised when my purple tree collard flowered in February. I was worried that the plant would die if it managed to set seed. I picked the 2 flowering stalks that grew and ate them. They were like purple sprouting broccoli in taste and texture. Since then it hasn’t sent up any more flower shoots.
I look forward to seeing what happens next year. Apparently it can live for up to 10 years. As insurance I’ll keep taking cuttings to propagate. If keep and grow even one cutting a year and older ones really do last 10 years, then I really will have that purple tree collard forest by then.