A good audience at the March meeting enjoyed an entertaining, extremely useful and practical talk from professional horticulturalist Ric Staines.
The basics of pruning: first of all you need a good pair of secateurs, preferably the bypass type. A holster is useful to save you losing them. You may also need loppers and a pruning saw. Always cut at an angle so the rain runs off the cut stem.
Why do you prune? Several reasons: to encourage growth; to restrict growth; to encourage flowering; to balance up or tidy the plant. Pruning can be routine, or renovation i.e. major pruning to an old plant.
The technicalities of pruning.: Firstly, take out the “D’s”: Remove Dead branches, Diseased wood, Damaged wood; and remove the Diagonal i.e. the jumbled crossing bits, especially in fruit trees. Keep the plant open to let the air to it. Take the top out to encourage side branching, cutting where you want the side branches to grow. Look for the “basal ring” which indicates the previous year’s growth. Do you want to restrict growth? Prune down to the basal ring. Is your shrub/plant not growing very well? Prune it hard.
When should you prune? If you want to encourage growth, prune in winter while the plant is dormant. If you want to discourage growth, prune in summer (late June or July). The plant will make a small amount of growth and then slow down for winter. The prime example of summer pruning is hedge-trimming.
Do you have an imbalanced plant or shrub? Don’t prune the stronger side, this will make it grow more. Rather, prune hard on the weaker side so that side will grow more (Ah, so that’s why my lopsided crab-apple tree has been getting worse rather than better!) To encourage growth, take more tips out, rather than a large amount on one branch.
Rick moved on to specific plants and members’ questions. (Apologies for not having room here to include them all!):
Prune plum trees, and other stone fruit trees, in summer, when the leaves are on. This will prevent the disease silverleaf, prevalent in winter, from getting into the pruned ends. Prune apple trees in winter. Apple trees are mostly spur-bearers with clusters of short branches on which the fruit buds form. Cut the spurs back to about two buds, cutting back to a bud facing the direction you want the spur to go. A few are tip-bearers with the fruit buds on the tips of long shoots. With these, try to encourage new growth by shortening the tips so that more form.
Flowering shrubs such as cistus and hebe will benefit from routine pruning; give them a general tidy up in late winter, before they start to grow. Do not routinely prune magnolias. Likewise, try not to prune daphne, except for minor tidying up. With shrubs such as Philadelphus, take out a few of the oldest stems each year.
Blueberries in pots, and fruiting shrubs: take out the oldest few branches, leaving the young branches to mature and produce fruit.
Wisteria should be pruned twice a year. The main pruning is in winter when you cut back to two buds, except for the main stems. Then in late June or July prune this year’s side growths back to four to six buds. This encourages the formation of flower buds.
Passion fruit, climbing roses, honeysuckle: try with climbers to create a framework. Train and space the shoots, trimming the side shoots back a little. Flowering will be better if you can train the plant horizontally, for example by zig-zagging it around a trellis.
Mophead hydrangeas: leave the big flower heads on over the winter. In late winter, remove the heads and prune to the buds you want to grow. Regularly cut a few old stems right back, to stop the plant getting too big.
Can you kill a plant by pruning? Yes. Lavender is a prime example. If you cut it right down, the bare wood will not grow. Prune it from a small plant. Trim it lightly after flowering, then give it more of a tidy up in late winter and early spring, pruning off last year’s growth. This will stop the plant getting leggy and straggly.
The next meeting will be on 16th April in the Village Hall at 8.00 p.m, when Herbie Collen will be talking about “My Secret Garden”.