My golden rain tree is sulking
An under-performing golden rain tree (Koelreuteria paniculata), is a cause of frustration for John Ross of Potters Bar. This unusual Japanese native with pretty leaves is also admired for the attractiveness of its clustered flowers which are then followed by equally eye-catching fruits. Having been given no less than 28 long years to find its feet, John’s tree completely refuses to flower and bear fruit as expected. Does it need a “mate”, he asks, in order to flower? Or is it time to give up on it?
Maybe I can clear up a cloudy issue here: like many trees and plants (from cherries to roses) koelreuteria is hermaphroditic and produces flowers with both male and female parts and is pollinated by bees – so if John can persuade his tree to flower, it should then automatically bear fruit. Dioecious trees, on the other hand – best known are holly and yew – are either male or female, and this is when you need a nearby mate for the female trees to fruit. Then (in order to complete the picture), there are monoecious trees such as hazel that bear separate male and female flowers on the same tree (so are wind pollinated).
In a garden, I inherited a rather paltry koelreuteria specimen. I eventually learnt this is a tree that won’t grow in the shade (which is where it had been planted) and actually flourishes in poor soil – so my heavy, basically fertile clay was clearly not appreciated either. Maybe John has been feeding his sulky tree too generously in an attempt to coax it into action. In his shoes, I think I would try a stricter diet: a summer feed of sulphate of potash (the “flowering” nutrient) and little else.
Looking around my garden I notice that quite a lot of my herbaceous plants are sitting up proud of the soil surface with the tops of their root ball showing. They were all planted last spring into newly dug and prepared beds. How can I rescue them? And how can I prevent this problem in the future? I have more new beds to dig and plant this spring.
Mahruk Bailey – via email
You may have thought at the time of planting that you did all the right things, but it sounds to me as if you may not have let the soil “rest” for long enough before you plopped your plants into place, and you may not have firmed them into the soil as well as you should have.
When you prepare beds from scratch, you inevitably create air pockets here and there that need to settle – you should ideally wait for at least a week or two before you plant. If you can bear to revisit the scene of the crime, gently lift out and firmly re-plant your one-year-olds now (which gives you a second go at adding goodies to the ground, such as bonemeal and more compost).
Make sure you plant them firmly. If you absolutely can’t do this, top up the beds with a really hefty mulch of compost. With your new beds this year, try to be patient and let the soil settle for as long as you can – and when planting, “put the boot in” to make sure everything is securely tucked in.
A pruning calendar
Do you know where I could get a calendar that tells you month by month which shrubs you should prune? I do rely on you to tell me when to prune things but surely there must be a blow-by-blow something-or-other that would act as a reminder? Jilly Bengough – via email
There are numerous pruning manuals, many that are almost too comprehensive. You might like to cobble together a “personal” pruning calendar of your own based on the following guidelines.
1. Shrubs that flower between January and mid-July should be pruned and/or thinned immediately after they finish flowering so they can make new growth that will flower in the first half of the following year.
2. Shrubs that flower after July do so on the tips of shoots they make in that current spring/summer, so can be cut back in early spring.
3. Evergreens grown just for their leaves should ideally be pruned just as the spring warms up. Those grown also for their flowers should be pruned after their main flush is over.
There is more to it than that, of course, which most gardeners learn by trial and error – or by picking the brains of friends or experts. I had a quick trawl around the internet for you to see what I could find and I suggest you look at this – which I thought was as near as it gets to what you want.