It’s happened in my vegetable garden again. I’ve got triffids, especially with the hot weather we’ve been having in Southland over this past summer.
For those of you who haven’t heard of the old sci-fi classic, a triffid is not the official name of a plant that you can ask for down at your local gardening centre. In the book from the 1950s by John Wyndham, a triffid is a carnivorous plant that can move and hunts down humans, with the risk that they are going to TAKE OVER THE WORLD!!!! In your garden, however, a triffid is any plant that threatens to take the whole lot over.
Triffids might be confused with weeds, but there’s one major difference. A weed is any plant that people haven’t found a use for yet. With a garden triffid, the plant in question is useful and desirable, but it’s spreading everywhere and is threatening to crowd out everything else that you’ve planted.
Sometimes, triffid behaviour is exactly what you want. The best ground covers for decorative gardening areas are those that spread fast and take up all the space so weeds don’t have the chance at any sunlight, space or water. Having a good ground cover is a very efficient and cost-effective means of controlling weeds in borders and garden beds – much cheaper and/or easier in the long run than continually weeding the garden manually and definitely better for you and your garden than having to use weedkillers. They’re even better when you use them in combination with a good mulch. Occasionally, you will have to trim back the ground cover triffid so it doesn’t overwhelm the other plants you actually want in the garden bed.
My favourite ground covers for garden beds are violets, native grasses, mondo grasses and Erica (heather). However, these aren’t the only ground covers that you can use in landscaping a new garden.
In the vegetable garden, triffids are a bit more problematic because you can usually eat or use the plant in question, and it seems so wasteful to pull it out. Take one of the most vigorous and enthusiastic triffids in my garden: strawberries. I love strawberries and they’re a delicious treat in summer. However, as well as producing lots of lovely berries (which you have to cover or race the birds for), they also send out suckers that go a surprising distance from the original parent plant. For some reason, it just doesn’t feel right to pull strawberry plants out in favour of broccoli and beetroots… Throwing strawberry plants into the compost heap seems even worse – and they’re probably likely to take the compost heap over as well. What I’ve ended up doing is to dig up the little “jumpers” and pop them into pots to give away as presents or to inflict on the neighbours.
Perhaps it was a mistake to have planted strawberries in the same raised garden bed as the rest of the vegetables. This was something I’d learned much earlier for mint. All species of mint are even more vigorous triffids than strawberries and keep on growing for longer. The best way to keep mint under control is to plant it in a large tub or a planter of its very own. Mint is very happy in shady spaces, so if you’ve got a spot in your garden that doesn’t see much sun and you want to do something productive with it, a tub of mint will thrive there with sufficient water, and keep you with enough mint to serve with roast mutton, add to carafes of water or mix with cucumber for a refreshing summer salad. Put it in your main vegetable patch and you will regret it – and because they can re-spawn from tiny bits of root, it’s very hard to get rid of.
I have occasionally wondered what would happen if I took an old bathtub, set it up as a planter (gravel down the bottom for drainage, then plenty of compost and potting mix, with a good dollop of sheep pellet fertilizer), and planted mint at one end and strawberries at the other. Which triffid would win?
Another surprisingly stubborn triffid that you might think that you have eradicated but haven’t is the common potato. Spuds can hide underground for years and pop up unexpectedly where and when you don’t expect them – sometimes years later. Years before we bought our place, our next-door neighbour’s kids used to throw potatoes at the cats yowling on the fence at night. Those kids have grown up, left home and had children of their own, but I am still pulling little potato plants out of the floral border under said fence…
Some vegetables can also become triffids but they aren’t quite as long-term. These quasi-triffids don’t clone themselves as they spread like strawberries and mint do, but they do take up a lot of space. Pumpkins are what I’ve got in my garden, a lot of which I didn’t plant on purpose. You know how it goes: you buy one commercially bred pumpkin from the supermarket on special in winter and chuck the seeds into the compost heap, then come spring once the frosts have finished, up they all come wherever you’ve used that compost. We’ve currently got pumpkins trailing all over the potato patch at the moment and sending little scout-vines out onto the lawn (the ones we planted deliberately are sending vines over the fence into the neighbour’s place). However, as I’ve got at least dozen actual pumpkins growing and ripening, I’m not complaining.
You shouldn’t avoid triffids of any type, whether you’re planning a vegetable garden or a decorative area. The golden rule is that if you know that something spreads like mad, put it in a tub or bed of its own so it doesn’t smother everything else. If you need help with setting up a raised garden bed, a new garden or a vegetable garden (or with pulling triffids or other weeds out from where you don’t want them), give us a call and we’ll help you out.