EXPERTS 4 PRUNING
Workshop: Pruning Fuchsias
1. What is Pruning?
Pruning is a regular part of plant maintenance involving the selective removal of specific plant parts. Although shoots and branches are the main targets for removal, roots, flower buds, fruits and seed pods may also be pruned.
We need to remove the terminal bud from all branches at least once a year in order to encourage the dormant or semi-dormant lateral buds to develop. Terminal buds produce a hormone called auxin that suppresses the growth of other buds close to them. This phenomenon is called apical dominance, and is why lateral buds close to terminal buds do not grow into side branches. Buds further away from the terminal bud get a weaker dose of auxin and at some distance from the terminal bud they are released from dormancy and begin to grow into branches. When the terminal leader is cut, the hormone no longer flows to the dormant lateral buds and they develop into side branches. (This also the rationale for pinching young plants)
2. Why do we prune?
a.) To train the plant.
To train the main structural branches to form the framework of the plant, especially for standards, bonsai, topiary, espalier, or other special shapes.
b) To maintain plant health.
Prompt removal of diseased, damaged, or dead plant parts speeds the formation of callus tissue, and sometimes limits the spread of insects and disease. Pruning a dense plant permits better air circulation and sunlight penetration. To avoid future problems, remove branches that cross and rub and interfere with each other. Pruning also allows better access for pest control.
c) To improve the quality of flowers, foliage and stems.
Fuchsias only flower on the tips of new wood so it is essential to prune out the old wood that has already flowered to encourage the development of strong new shoots.
Proper pruning of flower buds encourages early vegetative growth. You can also use selective pruning to stimulate flowering, or to produce larger (though fewer) flowers. Pruning of weak or spindly stems encourages the growth of strong new stems.
d)To restrict growth.
Pruning reduces the size of a plant so that it remains in better proportion to its surroundings or container.
e) To rejuvenate old plants.
As plants mature they become woody and unattractive. Pruning can restore vigour, and enhance the appearance of these plants.
3. When do we prune?
In the mild, frost free climate of the Western Cape we can prune from the middle May, and if we want good plants in full flower for the show in November or December we should finish pruning by the end of June. It is possible to wait for spring (late August or September) before pruning, but that limits the growing and pinching time available to your plants before the show. Whichever you choose, it is important to prune once a year, even if there are still a few flowers on your plants. Plants left to their own devices very rapidly get leggy and ugly, bearing few flowers at the ends of straggly branches.
4.What tools do we need?
First take care of your own comfort – this can be a long job!
a) Work surface.
This needs to be a sturdy surface in a shaded area at a comfortable height for you when standing or perched on a bar stool.
b) A bin or black bag to collect the off cuts, and rubbish you remove from the pots. Be sure to throw all your clippings away – we don’t need insect eggs or larvae or the spores of rust or botrytis around.
c) A small amount of fresh potting mix, and a couple of extra pots for those plants that need potting up, or just need a broken or old pot replaced.
d)A small amount of diluted Jik or Jeyes Fluid to clean your tools between plants and thus prevent the spread of disease.
e)Oil to lubricate your cutters when you have finished pruning.
f)The best quality cutting tools you can afford, freshly sharpened and clean. These might include:
Bypass pruners – These have sharpened, curved, scissor-type blades that overlap. They are generally quite slim and cut cleanly. I find that anvil cutters tend to crush the branches.
Surgical Scissors – devilishly sharp and small for getting into small spaces and making a perfect clean cut.
5. How do we prune?
Shelford looking very straggly and ready for pruning
a) Bushes.
1.Start out by removing any dead or damaged wood from the plant, and any branches that are crossing badly. Then step back and take a long hard look at the shape and structure that is left.
2. Now cut all the remaining branches back by about a half. This is quick and dirty cutting, just so that you can see the structure of your plant more clearly.
3. Begin to fine tune your pruning by cutting away all the thin weak growth. Weak growth will only produce weak shoots. Remove any dead or damaged growth that you missed previously. If branches are crossing, cut out the weaker one. This opens the plant up to receive more air and sunlight.
4.Now, for the detailed stuff. bear in mind that we are aiming for a fat round plant covered in leaves and flowers. Cut each branch back to two nodes of current year growth. Watch for any straggly bits that you might have missed and cut them right off.
Make a clean straight cut about 5mm above a node. We want to leave the smallest wound possible.
The current year growth is easily recognisable as the bark is smooth and shiny, whilst that of older growth is rough and dull, sometimes even flaky, depending on the age of the plant. This flakiness can be gently brushed off with a toothbrush or a rough glove to make sure no nasties are hiding under it.
This is usually about right for the newer tender cultivars that don’t always grow back from old wood. The older cultivars like ‘Display’, ‘Tom Thumb’, and ‘Phyllis” can be pruned really brutally if they need it, as they will shoot again from the roots even if they have been frosted right back. Use your discretion – if you know a particular plant in your collection to be slow growing, not very vigorous, or to have a weak root system, prune it lightly by cutting back each branch by only a couple of nodes after you have removed any dead or damaged material.. These are guidelines, not rules!
5.Remove all remaining leaves from the plant. They are going to fall off
anyway, and might be harbouring the eggs or larvae of pests or the
spores of fungal diseases so it’s best to get rid of them now. After
pruning your plants, you may find the ends of the pruned branches will
start to bleed. This is quite normal. The globule of sap leaking from
the branch end will be attacked by a white fungus which will feed on the
sap until the wound has healed. As the end of each pruned branch heals
the fungus will die. It will not harm the plant in any way. Seeing the
branch bleeding is a good indication that the branch is alive and it
will now maintain its shape and produce some nice sturdy growth. If you
are unsure whether any particular branch is dead just scratch the outer
tissue, the epidermis, with your thumb nail. If the wood beneath is
green and moist it is still alive. If hard and dry it is dead and must
be pruned back
6. Scratch all the debris from the top of the soil and remove about an inch of the soil. This also helps to ensure that you are eradicating any pests or diseases that might be lingering in the top of the soil.
Now is the time to decide whether you need to pot this plant up into a bigger pot, or you want to keep it in the same pot for another year.
7.
Slip the plant out of its pot and examine the root ball. Squeeze the pot
all the way around and tip the plant into the palm of your hand. If it
resists, tap the bottom hard and tug gently. If this still doesn’t
work, run the blade of a long knife around the edge of the pot to loosen
the plant.
If it looks as if there is still plenty of room for growth just slip it back into the pot and refill the top of the pot with some fresh soil mix.
If it is full of roots that are clearly visible it needs either to be potted up into a larger container, or have the roots pruned before being replaced in the same pot.
8 To prune the roots, gently tease out the root ball removing at least a third of the soil, so that you can see plenty of the long, thick roots.
9
Cut the long roots off all the way around, reducing the root mass by
about a third. Also take away any roots that look dead or damaged. Try
to disturb the small feeding roots as little as possible.
10.Clean up and thin out until you have a nice compact root ball. Sterilize
your old pot with a solution of Jeyes fluid, or use a new pot of the
same size.
11 Replant your bush in fresh soil mix, and water lightly. Remember to replace the label. Pruned plants all look the same!
You have finished now and new growth should start appearing in a couple of weeks.
12.Your plant is now ready to go back into the shade house, where you will spray thoroughly with a general pesticide like Chlorpirifos to kill off any pests that still may be lurking around.
After a week or so, a spraying with a weak solution of Magnesium sulphate (Epsom Salts) is a good idea as this helps to keep the ripe bark moist and supple and so facilitates the emergence of the tender new growth. I use 1 teaspoon dissolved in 5 litres of water.
Remember that your newly pruned plants have no leaves and, therefore, are not doing much in the way of photosynthesis or transpiration. They need only enough water to prevent the soil drying out, and no fertilizer until they show new leaves that are recognisable as true fuchsia leaves. When once recognisable leaves are present begin to feed again with a fertilizer rich in nitrogen and low in potassium such as 3:2:1. I also like to give at least one feed of Kelpac (about two weeks later) as the growth hormone content of this product really boosts the growth in the early stages.
b) Standards.
Standards are treated in exactly the same way as bushes. They are, in effect, bushes on long stems. Take care to keep a good balanced shape to form the base of a full, round standard. This is also a good time to check your stakes and ties and replace if necessary. You will probably need a second pair of hands if you are going to repot or root-prune a large standard – they are both heavy and unwieldy and you run the risk of doing yourself an injury, or even worse, breaking off the head, if you go it alone.
Before After
c) Baskets.
We treat baskets a little differently. Follow the same procedure described above up to step number 3. Then cut the plant back to the node nearest to the edge of the basket/bowl or hanging pot. Reduce the shoots in the centre of the basket to two nodes of current year growth, and continue from step 5 in the same way as for a bush.
Before After
d) Young Plants.
Very young plants, those younger than one year that might or might not have carried a few flowers, don’t need heavy pruning, but they must still be lightly cut back to shape them and encourage new growth. (I am not including your newly planted-out rooted cuttings in this – they are in a league of their own!) Cut 5mm above a leaf axil that is showing lateral buds. Don’t remove the leaves from these plants as they need all the leaf cover they have to survive. Spray them thoroughly and inspect them often to make sure they are not harbouring any pests. Recommence feeding when you start feeding your older plants.
Before After
That really is all there is to pruning.
Remember to clean all your tools carefully when you have finished, and
lubricate them well to prevent rust or corrosion. Good tools are
expensive and deserve to be looked after. They will serve you for many
years in repayment for a little care.
Glossary
Apex: the tip of a plant part.
Apical dominance: Inhibition of the growth of lateral buds by the terminal bud of a plant shoot.
Auxin: Naturally occurring (or artificial) plant growth substances controlling shoot growth, root formation, and other physiological processes in plants.
Axil: the upper angle formed between two structures or organs, such as a leaf and the stem from which it grows.
Bud: a developing leaf, stem or flower.
Callus tissue: a hardened or thickened area at the point of attachment, or sealing scar of a cut.
Internode: the portion of a stem between two successive nodes.
Lateral bud: A bud growing from a side node on a branch - as opposed to a terminal bud which grows from the very tip of a branch.
Node: a point on a stem where leaves or branches originate.
Photosynthesis: The process in green plants and certain other organisms by which carbohydrates are synthesized from carbon dioxide and water using light as an energy source. Most forms of photosynthesis release oxygen as a by-product.
Terminal bud: at the end of the branch or stem.
Transpiration: The process by which water absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface, principally from the leaves.
If you have any questions, comments, or suggestions please contact me.
Penny East
Contact details: yduff@telkomsa.net