The main tasks in the garden – pruning deciduous trees, pruning roses, bare-root planting – are projects which should be accomplished in January and not put off to February which will be too late.
Bare-root Planting
Only plants which go dormant during the winter can be sold in bare-root form. Mostly they are roses, deciduous fruit trees, deciduous trees and vines, such as wisteria, strawberries and some vegetables such as artichokes and asparagus. If you find any in local nurseries, this is the month to plant. Purchase them early in the month, keep them in a shady place until ready to plant, and don’t let the roots dry out. If they are truly bare-rooted without any packaging, soak the roots in water for an hour or two and plant right away. If it is not possible to do this, heel the plants in – dig a shallow trench in a shady spot, lay the plants on their sides with roots in the trench, cover the roots thoroughly with soil, water well. Plants heeled in can survive six weeks or so, but it is better not to leave them that long.
To plant bare-rooted deciduous fruit trees, choose a spot in full sun with good drainage and enough space for the tree to grow. Snip off any damaged or broken roots, and place in water while you dig the hole. Hold the tree in the hole so that the elevated bud union faces north and the original soil level (below the bud union) is 5 cm higher than the surrounding ground.
Backfill the hole, using as much original soil from the tree as you may have for its roots, then with local soil, press it down to compact it over the roots. Don’t add any soil amendments. Create a watering basin around the tree. Water deeply by allowing a hose on the ground to trickle water into the area until the roots are penetrated. In fast-draining soil, water often until the tree is established.
In soil with poor drainage, water when the soil begins to dry out. Gradually lengthen the intervals between waterings.
To plant bare-rooted roses, remove any broken or damaged roots, and place in water while you prepare the hole. Site roses in full sun, and dig a hole about 50 cm deep and 60 cm wide. Check for adequate drainage – roses thrive in heavy soil, but will not survive in swampy conditions. You will need to add compost but not manure in the hole (manure can be used as a mulch on top).Shape a cone of mixed soil at the hole’s bottom and firm it by hand. Put the plant on top, spreading the roots over the cone. If the roots bend at the bottom, you need to dig a deeper hole. The bud union should be 5 to 8 cm above ground. Backfill the hole and firm the ground, then form a watering basin. With a hose placed on the ground, let water trickle in slowly so that the roots are thoroughly watered.
In fast-draining soil, water daily for the first three days, then twice a week for the next three weeks. In heavy soils, check the soil twice a week and water only when needed. After that, water once or twice a week depending on need.
Pruning Deciduous Fruit Trees
All such trees need to be pruned annually to create good shape and to bear well. The only time to do this is when the trees are dormant and after the leaves have fallen but before new buds have swelled – usually this is December or January. Each type of fruit requires different treatment.
Apples require little pruning once the main frame of branches has been established. Fruit is borne on spurs that bear repeatedly, so do not cut off all the spurs. Remove all the leaves that have not fallen by themselves as the combination of old and new leaves can lead to apple scab, a fungal disease worst in rainy years.
Plums also bear on spurs and pruning is minimal for European plums while Japanese plums are so vigorous that new growth should be heavily pruned.
Apricots produce fruit on both one-year old branches and on older spurs which can bear fruit for four or five years. The older branches must be headed back so that one-fifth of the bearing wood will be replaced.
Peaches and nectarines require heavy pruning to force new growth as their fruit comes on one-year old wood.
Figs don’t require much attention other than to control the size and shape.
As pruning varies from variety to variety, the use of a specialist manual on pruning is recommended. After pruning, always tidy up under the tree.
Roses
January is the month to prune before new growth starts. Best advice is not to cut them down lower than your knee, leaving thick, healthy canes and cutting out dead, weak and twiggy ones. Ideally, four or five healthy canes should remain, five to seven for plants more than five years old. Make a straight cut, rather than a slanted one. Traditionalists may wish to follow the technique of cutting each branch close to an outside bud, but experiments by reputable bodies in the UK have shown that roses are just as happy being pruned by hedging shears without regard to buds.
Finish off the pruning by cutting the tops of the canes so that they are more or less equal in length. If any leaves remain, snip rather than pull them off. Tidy up the ground below, remove and burn all leaves, then mulch with compost or dried manure.
Don’t fertilise with nitrogen (contained in all ready-made rose fertilisers) until new growth turns from red to green in the spring.
Miniature roses can be treated similarly but on a scale appropriate to their size. Take the opportunity to shape ground-cover roses with shears.
For floribundas, cut out the centre branch from each cluster of branches, and cut the other ones back to three or four undeveloped buds. Leave more twiggy growth on floribundas than hybrid teas.
For climbing roses, don’t prune those under two years of age. Everblooming ones three years old or more can now be pruned. Ones which bloom only once should have been cut back after blooming has finished, but if not done, you can now remove old spent canes. For climbers on arbours, fences, or espaliered, these can bloom for many years on the same old canes; remove unwanted canes as they arise through the year. Eventually, these will decline in vigour at which point allow new canes to grow to replace the old ones.
The easiest time to remove suckers is after pruning. They sprout from the rootstock and if left to grow in profusion will eventually return the rose to its wild and unproductive stage, sapping its vitality along the way. Cutting them off only brings revenge from the sucker as it will sprout two or three new suckers in its place. The only way is to grasp it firmly in well-gloved hands, work it back, forth and around many times to loosen it and then pull with all you’re worth. This should tear it away from the rootstock. You may wish to dig carefully down to the sucker’s base to see what you are doing. For a sucker which has been allowed to establish for some time, you will certainly have to dig down to expose it and then try to shave it carefully from the rootstock.
Peach and Nectarine Trees
Peach and nectarine trees should be sprayed to prevent peach leaf curl, a fungal disease affecting the leaves and eventually the fruits. The first spray should have been in November when the leaves fell off the trees, and the second in January before the buds begin to swell. If it rains within 48 hours of treatment, spray again.
Citrus Trees
In coastal areas, January is the time to begin feeding citrus to promote more blossoms in February. In interior areas where frost may still threaten, don’t fertilise until March. Citrus requires lots of food, and should be fed monthly until June. Slow-release fertilisers are more expensive, but require less frequent applications – one in January or March depending on location and then again in June.
Apply the fertiliser on the ground 90 to 120 cm wide in a circle to cover the drip line. The main feeder roots of mature citrus are in the top 60 cm of soil beginning about 60 cm from the trunk and extending twice as far as the drip line. You can extend the fertilizer to cover this area as well, if you wish. Water the fertiliser into the ground, but do not work it into the soil.
Water mature citrus deeply but not too frequently – once every two or three weeks depending on weather. Citrus does not like to have its trunk wet, so make sure sprinklers don’t hit it. Apply water so it sinks into the ground around the tree beginning one-third of the distance from the trunk to the drip line.
Check for insects and disease and keep snails off the trees. Snip off leaves or branches which touch the ground.
Annuals and Perennials
It is a good idea now to add mulch around perennials before they spread out to cover the ground. Continue to deadhead where necessary. Cut back any plants which finished blooming. Trim lavender into form now and it won’t hinder spring bloom.
If you are in the mood for some instant colour for any bare patches, nip to a local nursery or two and see what is available. There should be some good choices of both spring-flowering annuals and perennials which can go in now, but wait for the rains to clear before doing any planting and be mindful of potential frost.
You can fertilise any winter flowering plants, other than wildflowers, with a feed containing plenty of nitrogen (for strong growth), high phosphorus (for bloom) and some potassium (general health). Don’t omit plants in containers.
Seeds – the best time for planting is in the autumn, but some might take now if sprinkled on well-prepared soil and raked in prior to rain. Keep the seeded area damp if the rain doesn’t. Heavy rain will dislodge the seeds, however. Try California poppy, clarkia, sweet alyssum.
Lawns
Keep mowing cool-season lawns, such as bluegrass, fescue and ryegrass and apply fertiliser every four to six weeks. A well-fed lawn is more resistant to disease. If you spot red-brown pigment on the blades with red dust, rust will have invaded but fertiliser should sort it out. No need to spray, just fertilise with nitrogen and mow regularly to remove the older, infected blades. Water if the rains don’t.
Soluble fertilisers with nitrogen on its own or with other nutrients should give cool-season grass a quick fix. Slow-release fertilisers cost more but last longer and are less likely to burn the grass and heavy rains won’t wash them out of the soil. Spread them carefully, being especially careful around corners, as any burns which result from too much chemical deposit will be difficult to get rid of.
Warm-season grasses, such as Bermuda and zoysia, are dormant now and need no feeding or mowing.
Vegetables
You can still put in transplants of broccoli, cabbage, cauliflower, lettuce or seeds of beets, carrots, lettuce, radishes. January and February are good months for planting bare-root asparagus, if you can source it, and bare-rooted strawberries, although November is a better time for planting strawberries.
Give vegetables still producing some fertiliser, if you did not do so in December, by sprinkling it either on top of the ground around each plant or down the sides of the rows. Do so just before a rain or water it into the ground. Harvesting veg is another time to fertilise, such as round broccoli when you cut the central head, lettuce after cutting the outside leaves. Onions need regular fertiliser now – it is best to feed them early in the season, then stop a month or two before they are ready to bulb. Liquid fertilisers, such as fish emulsion, are the safest way to feed onions now as liquids don’t stay long in the soil.
If you planted fava beans last year, they should now be waist high. Use bamboo sticks to help prevent them from being pushed over by rain or wind. If they bore flowers but no beans, pinch off the growing tips of the stems, then fertilise around each plant or down the rows. Beans should start to appear within a week. Wait until the pods are 13 to 20 cm long before you start to harvest.