Tag Archives: winter pruning

Garden lore: July 20, 2015 Petal blight, white camellia hedges and winter pruning

“One has a lot, an endless lot, to learn when one sets out to be a gardener.”

Vita Sackville-West, A Joy of Gardening (1958)

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Petal blight

Petal blight

After writing about Winter Whites last week, referencing the ubiquitous white camellia hedges, of course I noticed this hedge on my way to town. My eye was drawn to the composition of brown and white flowers. It is a japonica camellia, though which one I am not sure. Closer examination revealed a bad case of petal blight, even this early in the season. There are two main giveaway signs. The first is the brown flowers hanging on to the bush. Most modern camellias are what is called self-grooming. They are bred to drop their spent blooms but those affected by petal blight hang on. The blighters. The second sign is shown by turning over a brown bloom and removing the calyx that holds the petals together. There is the tell-tale white ring of death – fungal spores. There is no remedy. You either live with it or you remove the plants.
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I have never been a fan of japonica camellias for hedging. The foliage can go a bit yellow in full sun and both leaves and blooms are too big. Smaller leafed camellias, seen in the sasanquas, some of the species and the hybrids look much better. Miniature single flowers usually fall cleanly and disintegrate quickly, avoiding the sludgy brown effect below.

Camellia transnokoensis

Camellia transnokoensis

While our C. transnokoensis hedge needs to thicken up yet, we are charmed by its floral display. The sasanqua ‘Silver Dollar’ is also an excellent hedging choice. While the small flowers are nothing special viewed close-up, it is one of the first sasanquas to bloom for us and one of the last so it has exceptionally long season allied to compact growth and small leaves which are a good, dark green.

Camellia sasanqua Silver Dollar - an excellent hedging option

Camellia sasanqua Silver Dollar – an excellent hedging option 

While some claim that sasanquas can get petal blight, we haven’t seen it on our plants. And although the single flowered species and hybrids are not necessarily resistant, most set large numbers of flowers but each bloom only lasts a few days so they fall before blight takes hold.

On another topic, winter is pruning time. I did the wisterias on Friday. This is one plant family I recommend removing totally if you are not willing to prune them. They have dangerous proclivities. Most of the roses are done and I have started on the hydrangeas. Those in colder climates may be better to wait another month before tackling the last two because pruning encourages new growth which is vulnerable to frosts. The pruning guides I did several years ago as part of my Outdoor Classroom series give step by step instructions if you are not sure where to start – wisteria, hydrangeas, roses.

Garden Lore

“Few lend (but fools)
Their working Tools.”

Thomas Tusser Hundreth Good Pointes of Husbandrie (1557)

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Garden Lore: Winter Pruning

Winter and early spring are the optimum pruning times for most plants. Because the act of cutting back can stimulate plants into growth, timing can be important. Close to the coast, we only get light frosts so we never have to worry too much. But if you are used to waking to white ground and ice on puddles, hold back until the end of the month and leave the hydrangeas and roses until last.

Grapevines, raspberries – indeed all the brambles – and kiwi fruit need annual pruning or they will swamp you with their rampant growth. While pruning is recommended for most fruit trees, it doesn’t usually matter if you skip a year or two.

Always prune wisterias. They are as determined and rampant as kiwifruit. Roses will survive without pruning – although you may rue the day if you allow climbing ones free range and they look better for some care. Hydrangeas are pruned to increase flower size and to stop bushes getting too big. They will still bloom if you don’t prune them.

The critical piece of information you need is whether plants flower or fruit on last season’s new growth or on the new growth that they are preparing to make this spring. If is last year’s growth, as in hydrangeas, wisteria and raspberries, if you cut too hard, you simply won’t get any flowers or fruit this spring. Roses flower on fresh growth so you are pruning for shape and health and can cut back very hard. The same goes for grape vines. One size does not fit all in this matter.

First published in the Waikato Times and reprinted here with their permission.

In the Garden: Friday 9 July, 2010

Our citrus trees actually do save us money

Our citrus trees actually do save us money

  • Avoid stomping around the garden or lawn where you have spring bulbs. It is a hard life already for a bulb, pushing through cold, wet soils without being stomped back into the ground. Even worse, some only put up one flowering spike and if you break that off, you are sunk for this season’s display.
  • Prune and keep pruning. I am halfway through the roses but have finished the wisterias. The hydrangeas have been started. As luculias finish flowering, it is the best time to prune and feed them because their instinct is to spring into growth. It doesn’t pay to be too brutal with luculias – they can up and die on you. Regular pinching out or cautious renovation is recommended. They are not difficult to root from cuttings in late spring or early summer if you want to start afresh.
  • Sasanqua camellias can be pruned and shaped as they finish flowering. This includes sasanqua hedges but it won’t matter if you leave it until spring.
  • With our comparatively mild winters, we can lift and divide dormant perennials such as hostas all winter and spring. In cold climates where there is no growth over winter, recommended practice is to leave it until temperatures start to warm in spring (presumably divisions can rot in completely dormant, cold and wet conditions) – hence the different advice in books and TV gardening programmes from England. However it is wise to leave grasses, reeds, rushes and similar plants until they are growing again because they can be surprisingly touchy.
  • You can at least be planting your fruit trees which are now available in abundance. Put in the sure-fire crops first and go to the riskier, more exotic options if you have space remaining. Apples, pears, plums and feijoas are extremely reliable whereas it can be hit and mostly miss with peaches, nectarines, cherries and apricots. In mild coastal areas, citrus and avocados are well worth a try – for us they are the crops that save us significant money. Only buy named cultivars of feijoas – the cheapie plants are patchy seedlings for hedging and may never even fruit.
  • Get a winter strength copper spray onto deciduous fruit trees, citrus and roses as a winter clean up. This will reduce disease and lichen.
  • I have a new definition of a gardening optimist – the person who googled “sub tropical fruits Southland”. Southland may be many things, but sub tropical is not one of them.

In the Garden: June 25, 2010

The Monarch Rescue Centre

The Monarch Rescue Centre

  • Mark’s monarch rescue mission has resulted in a branch of about 100 suspended chrysalises which resembles a shish kebab. It moves around warm positions in the house but alas the successful emergence of healthy butterflies is at an all-time low. I don’t think even Mark is sufficiently obsessed to set up a long term rehabilitation and care centre for disabled and deformed butterflies, though he admits he has certainly thought about it.
  • You can still plant broad beans in the garden, along with garlic and shallots but generally, veg gardeners are now looking forward and preparing for spring plantings. If you have a favoured position, you can get the first sowing of carrot seed in but make sure you cover the row with a board or narrow strip of nova roof in order to keep heavy rain from compacting the finely tilled soil and washing the fine seed away.
  • • Potatoes will be coming into the garden centres. You need sheltered, frost free positions that get maximum warmth for really early crops, which tends to mean coastal area only. But anybody can be preparing now by chitting the taties – putting them in a single layer in a darkened location to encourage sprouting. Not all potatoes are the same and if you keep track of the different varieties, it is fun to buy a pick and mix selection to compare later. We are disappointed to find hollow centres in most of our large Agria this year (an otherwise splendid potato) which did not occur in any of the other varieties in the same location.
  • The great winter pruning operation should be starting. Deciduous trees, shrubs and climbers are generally winter pruned. Some, like rampant climbing roses and wisterias, need pruning to keep them under control. Some, like hydrangeas, apple trees, forsythia and many clematis or roses are pruned to maximise flowering and to keep a tidier plant. Some are only pruned occasionally as required, to remove twin trunks in a deciduous tree for example. In a small garden it is probably just as easy to work your way around the garden. In a big garden, it may be easier to work by genus – wisterias today, fruit trees or roses next week.
  • Winter is also the time to do a clean up spray on deciduous plants. Lime sulphur will clean up lichens and mosses and is widely used, as is copper at winter strength.
  • We are somewhat proudly still eating fresh green beans and corn on the cob harvested most days from the late plantings. The corn has lost its autumn sweetness but it is still fresh corn. The bean plants defoliated at the first hint of frost but the beans are still reasonably tender and good. They are a triumph of successional planting through spring and summer. Mark and dogs are almost getting a possum a night from the avocado trees. Apparently these critters love them just as much as humans. Even the dogs have developed a taste for avocado snacks.

Outdoor Classroom – Winter pruning Hydrangea macrophylla

The common hydrangeas grown here belong to the macrophylla family. These give us most of the traditional mop-tops along with the flat heads of many lace-cap varieties. Less common hydrangea species (the ones with oak leaves, cone flower heads, evergreens and the like) often have different pruning requirements.

1) It is not essential to prune hydrangeas. They will still flower if not pruned but you will usually get many small flowers on a bush which grows ever larger. Pruning takes place to keep the bush smaller and tidier and to encourage bigger blooms.

2) Most hydrangea stems will have a series of buds in pairs visible down their length. The fat buds are flower buds. The thin, small buds are leaf buds. Ideally you want pairs of fat buds, because that will be two flower heads but sometimes you find one fat bud paired with a small leaf bud. You will only get one flower from that spike.

3) Using secateurs, prune back to the lowest pair of fat buds. If that is still much taller than you want, trim back to the lowest single fat bud.

4) After you have reduced the height of each stem, look at the clump and take out any really old, thick, woody stems and any spindly weak ones. You can also take out stems which are headed sideways and those with no flower buds if you want to keep your bush more compact.

5) Because most hydrangeas flower on last year’s growth, if you cut too low down and without taking any account of the difference between leaf buds and flower buds, you will have cut all this summer’s flowers off. You can cut off near to ground level if you want to rejuvenate an old plant and it will shoot again but you will have to wait 18 months for flowers. We have pruned for flowers on this plant.

In the Garden: June 18, 2010

Pleione bulbs

Pleione bulbs - discard the mushy, dark ones like the specimen to the left

  • The winter solstice or shortest day of the year is nigh – this coming Monday in fact. Alas the worst of the winter weather hits after the shortest day but at least you can console yourself with the thought that the days are lengthening again.
  • Traditionalists will be out planting their garlic (ours is in already). If you don’t have big fat cloves saved from last season, then make sure you only buy New Zealand garlic for planting. The cheap Chinese garlic comes from the wrong hemisphere so is out of its seasonal cycle and is reputedly riddled with virus which threatens our local garlic industry. You also have no idea what it has been treated with so it is all round bad practice to buy cheap imported garlic for planting.
  • Asparagus is a luxury crop for the home gardener because it is a permanent plant which takes up space all year for a harvest lasting only six weeks or so. It also takes a few years to start cropping well so is unsuitable unless you are planning on staying in the same place. But for those with space and the long term commitment, heading out to pick some spears in spring is a gourmet experience. If you have a patch, now is the time to clean it up and spread a blanket of compost to feed the crowns below the ground and to suppress weeds. If you have plans to plant an asparagus patch this spring, then get in now and dig the area. Then double dig it. Add as much compost and manure as you can and dig it yet again. Then let it rest and mature before planting in a couple of months time.
  • Winter is the time for pruning all deciduous plants except for cherries (both ornamental and edible) and plums which are summer pruned to prevent silver blight getting in. Gardeners in cold, frost-prone areas are best to leave their hydrangeas until last (pruning encourages growth which can then get burned by frost). But wisterias, roses, apples, grapevines and the rest can all be tackled over the next six weeks.
  • We did Outdoor Classrooms last year on pruning wisterias and grapevines (these are on http://www.abbiejury.co.nz and on Stuff (Deb, are these still accessible on the Fairfax site?) We will be looking at pruning roses and hydrangeas shortly. Don’t cut your wisteria off at ground level if you want flowers this spring.
  • Most spring bulbs are in growth already so it is time to look at planting or lifting and dividing the summer bulbs – particularly lilies.
  • Pleione orchids are spring flowering but now is the time to clean up clumps and repot because they are still dormant. These are a most attractive and hardy ground orchid, often called the teacup orchid. If you look after them, they build up quite quickly and we find them useful for carpeting woodland margins where conditions are open. The prized yellow ones like a winter chill so will do better inland and in the south but we find the pinks, lilacs and whites are equally at home in milder areas. It pays to clean them up now (discard the soft, mushy black bulbs and keep the fresh green or red ones, trimming off last season’s dead roots) because root disturbance on pleiones once they are in growth is a no-no.