How to sow, grow and stake cosmos

How to sow, grow and stake cosmos

Cosmos is one of our absolute favourite plants here. They give you the highest square inch productivity of any other cut flower, so for every square inch that you plant up with a cosmos, or square foot or whatever, you will get more buckets of cut flower from that square foot than you will with any other plant, so that’s why they are just fantastic and they have a very good vase life.

 We grow lots of different varieties, five or six different varieties here; one of my favourites is this, which is called Cosmos ‘Dazzler’. You can sow cosmos in two ways, either you sow it under-cover in March or April in a little module, two seeds  into a module and then if both germinate you just remove one a week later and leave just one to grow on in splendid isolation. Then they just get put out in the garden spaced at 14 to 18 inches apart and that's exactly what we've got here.

There is another way to sow them though which I’m going to show you, which is direct. This is a row of Double Click Cranberries which we direct sowed in April and by April here at Perch Hill the frosts are usually over. So what you do is you sow seeds two to three inches apart and then you go back about three weeks later and you thin to about 12 inches and you can go back at the next stage about a month after that and actually thin to 18 inches and we haven't done that with this row but you can do it as long as you water well before you plant the transplant rather, and after when they've gone to their new home then they should survive fine and so literally it's just very very quickly scattering see but you've got to have a fine tilth and that's what we've got here.

So back here again the next thing is once they get to this sort of height you want to stake them and there are two ways of doing that and so I'm going to put this beside each individual plant, a bamboo cane like that and then I have got some Flexi-Tie here and what I'm going to do is I'm going to cut a length about that long, about two foot long and then I do a forward loop like that and then another forward loop like that and then I tuck the second rabbits ear behind the first. I don't rotate I just tuck it behind that, then goes down over the bamboo cane a little bit higher up than the last one and you tighten it and the beauty is that's not going to slip. Then I need to try and tie in every single one of the stems of this plant because otherwise the outer limbs just get broken off when its windy, and that then can come back and tie back into the other end. Now that's quite a utilitarian way of doing it but you know the funny thing is it works and you will actually not notice that that is staked at all in a matter of a couple of weeks because the leaves will grow over it.

 There is another way of staking which I'll show you in the other garden which is growing up through netting but while we're here the final thing that's important with cosmos is that you either need to pick or dead-head on a regular basis so we try and pick and deadhead at least once a week. When you're picking or dead-heading if you're dead-heading you just want to cut down to the main stem, between the main stem and a leaf. You will then promote exhilarate bud formation so by me removing that you will then get another bud forming in there. That would be next week's flower but obviously if I’m picking, I want a slightly longer stem than that ideally. So I’ll go lower in the plant so I’ll come to here so again main stem leaf, so that would be an auxiliary bud forming in a week or two’s time so I removed there or I can come down to here, for the same reason I’ll get auxiliary bud formation. If I’m doing a bigger vase I can come to here and you can see already there's an auxiliary bud between the main stem and the leaf, that's the auxiliary bud and that is the flower for a few weeks time. The lower you go in the plant obviously the more delay you will be between the flower you've picked here and the next flowering the nearer you go to the top of the plant like that by removing that one I'm going to promote auxiliary bud formation, but obviously that will be in flower in a few days that will be in flower in a couple of weeks.

 This is another variety of Cosmos that is one of our absolute tip- top favourites as well which is called Cosmos ‘Purity’ and it's a wonderful wonderful plant but I just brought you in here into the cutting garden to show you the different type of staking. This is grown up through clematis or pea netting and it doesn't look great when you first put it on but, I promise you it just appears really quickly as soon as the plants grow up through it you just don't notice it's there and you can have these sort of robust stakes. We use our own hazel, but you or you can use a bamboo cane and you just make sure that it feeds over that and it's taut between them and then the plants just grow up through it and it's enough support so that if you get a windy day or really rainy night, they don't collapse over onto their hip and once they do, of course what happens is that they fall over onto their side, then the light takes all the growth tips of all the new growth straight up towards it so you then get a stem going like this. Then if you stake it you then have it looking like that but unfortunately it then does that, so you get this crooked / sort of corkscrew stem which isn't great for cut flowers of course, so staking with cosmos or with all your annuals that get to about two feet it's really really important.