In last Wednesday’s post (What doesn’t grow in my garden) Don of Iowa Garden deplores the fact, that so common plants as aquilegias can’t be persuaded to find a home in his garden while other rare and difficult-to-grow ones are thriving. I’ve often made the same experience that there is no way of forcing plants into your garden. Sometimes moving them around to a more suitable place helps, but some plants simply vanish despite all efforts.
For example Pulsatilla vulgaris simply thrives in my garden, seeding itself all over the place so that I regularly give seedlings away to my parents in whose garden they disappear after a season or two. The same thing happens with catnip, which I almost count among the weeds, however, it can’t be made to settle in my parents’ garden. I’ve made the reverse experience with cosmos flowers, which self-seed in my parents’ garden but which I can’t persuade to stay longer than a season in mine.
Neither the spot they were planted in, nor the conditions of the soil (sandy for Pulsatilla, any for catnip as long as it’s not too acidic), nor unfavourable weather conditions seem to have been the reason for their disappearance. So it is very likely that they were driven out by the presiding inhabitants. Even if I’m no biologist, I’m quite certain that there is quite a lot of interaction between plants that we are hardly beginning to understand. If potatoes can warn their fellow plants of a bug attack by emitting certain chemicals then it is quite possible that other plants have found ways of keeping unwanted neighbours out, for example by influencing the chemisty or microfauna of the soil. I know this for certain of Walnut trees whose decomposing leaves change the chemical makeup of the soil and thus make it difficult for other plants to grow below them. And vegeteble gardeners have learned from experience that some plants make good partners, such as onions and carrots, while others hinder each others’ growth; e.g. it is not such a good idea to have plants of the onion family grow next to peas. So it seems that just like humans plants have found ways of signalling to newcomers that they are not welcome.
In fact, this goes both ways: plants that I don’t like, don’t stand a chance, even if I try to find a nice place for them out of respect for the person that gave them to me. Begonias are to be counted among these. I keep dropping hints towards my mother (who loves them), that giving them to me means their certain death….