Pruning to perfection
July is pruning time in the garden. Find out more about the pruning of roses, fruit trees and hydrangeas.
Pruning should not be a dreaded chore. With the right tools and correct information, pruning can be easy. Think of it as a late winter cut-back that rejuvenates plants and prepares them for a summer of healthy growth, glorious blooms or fabulous fruit.
There are two reasons why roses need to be pruned – to encourage better blooms, and to keep the bush young and vigorous. They need to have old wood removed every three to four years to make way for younger, more vigorous branches. Spindly growth is removed so that the bushes will bear bigger and better flowers.
When should I prune?
Renowned rose grower and pruning expert, Ludwig Taschner, says roses should not be pruned before mid July in most regions of South Africa. In areas where night frost is still very prevalent, pruning should be delayed until early August and even late August in the eastern Free State. In frost-free coastal regions and on the Lowveld, pruning should be done in early July.
How much should I prune?
Ludwig says, “Whether you prune lightly or severely, each approach has its benefits.”
- Severe pruning enforces rejuvenation, produces roses of a uniform height and stimulates the production of long stems. In well-prepared, well-aerated beds and with the appropriate aftercare, bush roses will happily and quickly re-grow after a rigorous cutting back. However, not all varieties are capable of re-growing roots continually and they may die or perform indifferently.
- Light pruning allows the rose bush to develop a wider, deeper root system that helps withstand variances in watering frequencies and quantities, soil temperatures and, to a degree, balances out any over- or under-feeding. The basal stems form thicker wood that insulates the sap from heat and helps prevent sunburn and stem canker. This is possible because light pruning retains more wood, containing starches and sugars, which activate more eyes to sprout. While the upper shoots are developing into long stems the lower shoots quickly turn green and these shoots are able to photosynthesize the plant sugars and send them to the roots, activating the root development and spread.
Tools for the job
A sharp secateur, long-handled lopper and a pair of strong leather gloves will make pruning easy. A saw is needed only when really old roses that were pruned lightly for years are to be cut down. A useful aid is a strong measuring stick, which is clearly marked at a height of 50cm, 70cm and 90cm, allowing 10cm to go into the ground.
- Start by removing all the leaves and dead flowerheads.
- Then remove all the dead, diseased and damaged stems. Cut them away at their lowest or base point.
- Remove spindly and weak growth that is unlikely to be able to support buds or clusters of blooms.
- With all bush and shrub roses, cut away all stems that cross the centre of the plant. Aim for a vase-shaped bush that ends up with four or five strong stems around an open centre and avoid leaving stems that cross in the centre.
- Decide which four or five stems you wish to retain and cut these stems back to knee height (50-75cm). Ludwig says, “The height of cutting back still remains a personal choice. I have pruned our roses for many, many years at knee height with most satisfactory results. Pruning back to an 80cm and even a 1m height does not kill a rose nor does it have much of an influence on the quality of the blooms expected in spring.”
- Traditional pruning methods suggest that you make the cut just above a dormant, outer-facing bud. The rationale is that this will ensure that the new stems will grow out from the bush, not inwards towards the centre of the bush.
- How to cut? The latest theory is that a straight cut (as opposed to an angled cut) exposes the least amount of stem to the air and is unlikely to collect water (and therefore fungal diseases) as no stem is ever completely 90 degrees to the ground.
Ludwig recommends that after pruning, check out the friability of the soil around the roses by digging down by about 30cm. If the fork is pushed down easily to this depth, spread a little organic material such as compost, milled pine bark or manure over the surface. Sprinkle superphosphate and a fertiliser such as Vigorosa 5:1:5 (25) over the compost at the rate of 30g each per bush or square metre. Dig this all in, mixing it well into the upper 15cm, but water first if the soil is very dry. After digging, drench the bed well to get water right down to the roots and to settle the loose soil.
If the moist soil is very hard and difficult to penetrate with the fork, Ludwig advises that you use a coarser organic material. Add rough milled pine bark or peanut shells to the compost along with the fertiliser and dig in to a depth of about 30cm. “Just be careful when you feel a strong root in the way; re-locate the fork rather than forcing and loosening such roots,” he says. Afterwards, water your roses well.
It is a good idea to spray the pruned bushes with Ludwig’s Insect Spray. No sealing of the cuts is required. “If you cannot yet get this Insect Spray, use either a solution of Lime Sulphur 1 to 5, or spray with Citrex or Oleum at 100ml in 10 litres of water, adding an insecticide such as Garden Ripcord,” says Ludwig. After pruning, water weekly until the end of August when watering can be increased. Ludwig’s final tip: Rather wait with mulching until end of August, when the soil warms up.
Fruit tree pruning
July is also the month to prune fruit trees to ensure a plentiful supply of fruit during the summer months. Why should fruit trees be pruned? Simply put, it is done to encourage healthy new growth, remove dead and diseased wood, control the height of the tree, and, most importantly to promote blossom, thereby increasing fruit quantity and quality.
How to prune a fruit tree
The method of pruning fruit trees in their first couple of years is basically the same for all deciduous fruit trees – quince, peach, plum, apple, pear, cherry or almond. The first three years are vital years for establishing the subsequent growth patterns and shape of the tree, and correct pruning is essential.
Deciduous fruit trees bought at a nursery are usually one season old. Transplant the tree into a sunny spot. As soon as it has settled, remove all side growth and prune the central stem back to knee height (50cm). This may seem rather drastic, but this early severe pruning is a good foundation for a successful future. During the next season of growth, many branches will develop.
Pruning a two-year-old tree:
Look closely at the many branches that have grown during the summer and identify three or four good stems which will give the tree a cup-shaped structure. Prune these stems to a height of 75cm and remove all other growth.
Pruning a three-year-old tree:
The aim of the last prune of the formative three years is to establish a second framework. This involves selecting three good shoots growing from each of the three or four stems chosen the year before. Prune the selected three new shoots on each branch back to a uniform length of 50cm.
The flowering of hydrangeas at the end of the year can be controlled by when you prune them in winter. Examination of the plant will show that there are different types of wood, according to age. There are young, slender growths of the previous summer reaching up from the base of the plant. At the end of this stem there is a large bud. This bud, in the next growing season, will produce a short shoot and then a flower. Do not prune this stem.
There are also older shoots two seasons old. At the end of these stems there is a dead flower (if this has not been removed by dead-heading during the summer), while a short distance down the stem will be found a cluster of large buds, usually four to six in number. These, if left, will each produce a flower the following summer. All that is needed is to prune the stem back to just above the cluster of buds.
Older, heavier stems of two or more seasons will also be found, carrying several dead flower heads. These should be pruned back hard to the base of the plant to stimulate new vigorous growth the following season.