September is really the end of the shrub cut back period as I understand it but I’ve learned some lessons: -
- Shrubs and Bulbs. Try to get all shrubs shaped up to the size you want before the end of September. The ideal time is from late July onwards but it’s not too late to finish the job now. And plant Spring bulbs before mid October.
- Yew. Trim back the yearly new growth any time from late July but if you want or need to really reduce a yew do it in April May. Avoid a frost but do it when the sap is rising strongly and, with luck, new leaf shoots will then gradually develop even where cut right back to the ‘brown’. If you don’t do this periodically the yew will slowly but surely get too big / wide for its location. But, I guess that it’s better to do a hard cut back all over so that the sap doesn’t have any easier green areas to concentrate on even if this means that the yew takes more than a year to regain its beauty. I will let you know if mine dies when I do this next May !
- Magnolia. If you have a deciduous magnolia and even if it is still showing some second flowering, now - or, preferably, a month or two ago – is the time to really reduce it if it needs it. Unfortunately this means getting into it after its Spring flowering and when it is in full leaf. Leaving this work until the leaves have fallen is not good policy. The next year’s flower buds start to form quite quickly after the leaves come out and the earlier you dive into the fully leafed tree to reduce the new shoots, the more you will enable the next year’s flower buds to form where you want them. Also take out all ‘inward’ growing new leaf; all dead and inward growing branches, all those rubbing against another and all top growth that is just getting too high. The more ‘open’ the top is the better.
A real cut back will produce a forest of long ‘water shoots’ as the result of the roots ‘fighting back’ to repair the loss of branches. Don’t despair ! Just take out all weak new shoots, thin out the strong ones completely and reduce the one’s you want to keep to no more than the first or second ‘outward’ facing bud. These ‘water shoots’ will produce flower – eventually! Don’t leave short stubs of thick branches; it is better, if you can, to take them right back close to the trunk.