Thanks,
Dominik
I have a Portuguese Laurel (prunus lusitanica angustifolia) bush, about 170cm high, growing in Zurichsee area. I would like to heavily clip it into a small tree form. When is the best time of the year to do that? I do not care about not having the flowers this season.
Dominik,
Without knowing this plant specifically I would say that this year is probably not a good one for a drastic pruning. Last year's long dry summer, combined with the missing winter are probably stress enough without you introducing another.
Apparently, according to this interesting article, you can prune it hard without ill effects:
and
You could probably prune it whenever you want!
Ouch- most gardening forums will say that it is an awful plant- that suffocates all around it and underneath it- and should be avoided at all costs (sorry).
You can indeed prune it hard almost anytime- but wear gloves as it contains cyanide and is very dangerous to cattle and other animals.
Odile, thank you for your concern, but I think you're exaggerating a bit. Where we live almost every other house has one or a couple of Portuguese Laurel. The leaves and unripe fruits are indeed poisonous, but the fruits are edible when fully ripe. The Royal Horticuktural Society has given Portuguese Laurel their prestigious Award of Garden Merit in 1993, therefore it most have some merits
FYI, half of the garden plants are poisonous, such like ivy, hortensia, some specifies of rhododendron etc. For example, narcissus is super poisonous.
Ah well... Would much prefer a mixed hedge, or as we had in the UK, a yew hedge (mind you this is very poisonous too, so always wore gloves. A common cause of death for bow makers in medieval times. As our hedge was about 100m- we always gathered all clippings to give to cancer research. No hedge here - pheew- much to the delight of OH- trimming that 10ft yew hedge twice a year was a massive job.
Be that as it may, I am still interested in having the answer to my original question: When is the best time to prune? For example, it is OK to prune in early March, when there is still a possibility of frost? How does pruning affect the plant's growth hormones? I'd like that it grows vigorously, but not in a bushy way.
Did you not read my post?
Prune it when you want. It will be fine.
I found another article which states, for some topiary Laurel, they prune:
Tom1234, I have read your post, thank you. Do you have personal experience or did you just web search for this info? Your article is from UK where the climate is different (much lesser likelihood of frost), same for your second quote. Many other articles don't recommend pruning before April. Because of confusing information I asked this question here, hoping that someone with personal experience of gardening in Swiss climate zone will answer.
Just depends on altitude and local microclimate. There is no 'Swiss' climate, and neither is there a 'UK' climate. Cornwall or Yorhsire Dales would show different dates. I'd do it as soon as Spring as sprung. (we have about 4ft and more of snow here where I live in the Western Jura.
I've got loads of shrubs and bushes here in Switzerland (but not your particular laurel) and none have ever died from being pruned in winter (although some actually get their main prune after flowering).
Pruning when dormant is a lot safer and less of a shock to the plant than pruning when actively growing (if you're not sure when to prune something).
If the plant grows outside in winter here then you can prune it in winter.
Odile, there might be no Swiss climate (although we probably agree that anywhere in Switzerland can snow in the winter and that summer temperature is almost never above 40C), but I've specifically said I live the Zurichsee area, which has its own microclimate.
To cut back Portugal laurel hard, it is best to do so in early spring, just before new growth starts, that way the plant grows back strongly and you reduce the chance for die back to occur .
If you are removing lower branches to have a clear stem and to create a tree form than ensure that you remove the branch completely (no stubs) back to the branch collar. but avoid cutting into the trunk!
For maintenance clipping of the foliage to maintain the height and shape, than it is best around midsummer as the plants new season growth will have finished at this time and the regrowth after cutting will not be too strong as a result. cut with a sharp hedge cutter for a very tight form or by hand with secateurs for a more natural look.
The laurels are tough as nails and with the following precautions regarding clipping they should be problem free. pruning and clipping hard during hot or very cold weather exposes the lower leaves to more heat and cold than they are used to and they can get a sun or cold burn. although not fatal it can be unsightly causing a yellowing or bronzing on the leaves. so where possible avoid hard clipping during extreme heat (Above 25C) or cold(below freezing) generally plants adapt to the new light levels and after about a week or two the leaves toughen up!
Feed your plants by top dressing with up to 5cm garden compost in spring which will provide balanced growth. Mulching on top of the compost with wood chip or bark mulch will help to keep the soil nice and moist during the summer months and keeps down the weeds. I hope that helps.Good Luck!
Treebeard, thanks a lot for a great expert answer!