I ought to be ashamed of my cosmos. And I am.
When you know how good it can be; how tall, wide, strong – muscular, even – then you know that this is a pathetic effort, if not quite a total fail.
I love cosmos. I think I just generally love simple annuals. But what I’ve come to understand is that while cosmos will produce a flower or two on a mean little upright stem under the very worst of conditions, it’s capable of producing thousands of flowers on a great shrub-like structure under the best conditions. It’s one of those annuals that’s dead easy to grow, but not so easy to grow really well. That specification may not be uncommon with annuals, but my experience would suggest that the destiny of any cosmos plant, in particular, is set from a very early age.
I used to be a shocker for buying a punnet of seedlings weeks before I wanted to plant it, or at least delaying for weeks for no good reason, during which time the wretched things would be allowed to dry out until prostrate, only to be re-hydrated just moments before their last gasp. I admit to being kind of fascinated by this capability – by their resilience. But what I’ve since come to understand is that this process nearly always triggers responses that leads to a less than happy outcome. And particularly with cosmos.
This is never so obvious than when you compare the performance of plants sown in pots or trays and eventually planted out to those that self-sow, or are direct-sown into the garden. The former plants are likely to be in flower much sooner on a much smaller, less branched plant than the latter, which (in reasonable soil, at least), is likely to branch up and build into a solid hemispherical mound before producing its first flower, and then continue to flower heavily for months. My suspicion is that while they go through the process of being pricked out as seedlings, grown on in pots and transplanted into the garden with apparent ease, any stress during this phase triggers premature flowering. I’ve found that while the almost inevitable stresses of this process can be minimized, my less-than-perfect attentions aren’t likely to manage it. These plants were sown too early indoors, then had to sit around in the seed pot for too long while I waited for the weather to warm up enough for them to brave the outdoors. This is not fatal. In fact it’s deceptively non-fatal. The plants look fine, but their fate as mediocre performers is irreversibly set.
Ongoing starvation and/or drought can induce premature flowering in many annuals, as they rush to set seed (if you’ll forgive the implied teleology) before a premature death. What I’m interested in here is how early in the life of the plant that response is induced. Other tall branching annuals may well show the same thing, but I’ve not seen it as clearly as with cosmos.
On the other hand, annuals which grow from multiple, lax stems that branch out from a basal rosette at ground level, like pansies, violas and petunias seem much more tolerant of neglect earlier on, even of the unforgivable McCoy-neglect, which I’m glad to say I’ve grown out of. It’s as if, once they find themselves in favourable conditions, even following a pretty rough youth, they seem capable of virtually limitless sprouting from the base, and a perfectly satisfactory display.
All this makes me very cautious about buying punnets of seedlings of the taller branching annuals. When it comes to cosmos, caution leads to total avoidance. I want to either have grown them myself, or have them come with a full service history.