May

How to cope with your garden this May.

Drought is a serious concern for many gardeners this summer as hose pipe bans come into effect. Bedding plants, the bedrock of many summer displays can be particularly vulnerable to drought unless you choose your varieties with care. Types to avoid include begonias, bedding dahlias (larger dahlias are fine), fuchsias, impatiens, lobelia, pansies and phloxes which all suffer badly if they run short of water. In their place try the more drought-tolerant alyssum, dianthus, cineraria, French marigolds, gazanias, pelargoniums, mesembryanthemums, osteospermums and zinnia. All of which will put on a good display when the soil is a little on the dry side. In my garden I’ve already invested in more water butts at the foot of rainwater downpipes. Apart from anything else, plants seem to prefer rainwater to the stuff that comes out of the tap!

Drought-tolerant plants are also a good choice for containers because they will recover more quickly if they are inadvertently allowed to run short of water. If you’ve a couple of pots in your garden that always seem to get forgotten, plant them with the brightly coloured bidens, portulaca and pelargoniums which are tough enough to survive periods of drought and soon produce a new flush of blooms when given a good watering. To give the displays a bit of substance add drought-tolerant foliage plants, such as Cineraria, Helichrysum petiolare and plectranthus. As a general rule, you can keep watering containers to a minimum by choosing the largest you can afford which will hold a lot more compost and so require watering less often. For example, a 40cm-diameter hanging basket holds nearly three times as much compost as a 30cm basket. Other easy ways to cut down on watering include adding water-retaining gel to your compost at planting time or choosing one of the special container composts designed for the purpose. You can also add water-retaining gel to existing pots by spiking a series of deep holes in the rootball and trickling in the water-holding crystals before topping up with water. It’s a good idea to line porous containers such as terracotta and concrete pots with polythene before planting (taking care not to cover the drainage holes) to help prevent water evaporation through the sides of the containers. Or soak the pots before planting by standing them in water for a couple of hours, so that the containers don’t draw water from the compost once planted up. Wire hanging baskets can be lined in the base before adding compost to act as a water reservoir. The easiest trick in the book that’s often overlooked is to position your containers somewhere sheltered and sunny for part of the day, but not too hot. Permanent containers, that have been standing on pot feet all winter to prevent them getting waterlogged, should now be stood in shallow saucers designed to catch any water that runs through the container at watering time, so it can be absorbed by the compost. You can invest in one of those pot-moving trolleys, so that you can move drought-prone containers into the shade during the week and place them on parade in the sun at weekends. You might find that this alone will cut down watering requirements from twice a day to once a week!

IN THE GREENHOUSE

I’m not a great fan of automatic watering systems, as a rule, but in the greenhouse they’re a godsend. If you are growing a lot of plants from seed or cuttings, or have a lot of small potted plants, some form of bench watering will save hours of toil each week and avoid disappointment. A friend of mine has two simple systems; a sand bench that’s kept permanently moist by buried leaky pipes, and a temporary capillary bench for his propagation production line. This last one is particularly easy to set up and costs very little. You’ll need a sturdy, perfectly level bench which should be covered with a sheet of polythene before the matting is laid on top. To make watering semi-automatic, fix a short piece of guttering fitted with water-tight ends to the bench and drape the edge of the polythene and the matting into the guttering. The guttering will act as the water reservoir keeping the matting constantly moist. Then, simply stand the containers on the matting and water them from above to start the capillary action going. Check that your pots don’t have ridges on the base because this can inhibit water uptake. Permanent greenhouse pots up to 15cm (6in) deep can also be watered in this way. Larger pots will need additional wicks (easily made from thin strips of capillary matting) pushed through the drainage holes to ensure thorough absorption.

Large individual pots and growing bags as well as plants growing in the border can be watered using one of the many drip or trickle irrigation systems. One of the simplest has water running from a bladder bag hung in the greenhouse. The bag acts as the reservoir slowly dripping water at the base of the plant – like a saline drip alongside a hospital bed. Alternatively, there are systems that have micro-bore tubing delivering a constant supply of water via drip or trickle nozzles that can be adjusted to suit the needs of each plant. Bear in mind that all these systems need regular checking (at least once a week) to make sure they are working properly and water reservoirs need routine topping up.

Check, too, that under the restrictions imposed by some hose pipe bans, automatic watering systems can still be used. Your local water authority will offer up-to-date advice.

Essential greenhouse jobs
  • Keep the greenhouse cool by careful ventilation, shading and damping down
  • Train tomatoes and cucumbers planted last month
  • There’s still time to sow cucumbers and melons
  • Plant peppers and aubergines
  • Take softwood cuttings from many shrubs (see below)

MAY LAWN CARE

After a slow start to the year, grass is now growing with a vengeance. If you have just moved house and inherited a neglected lawn or the grass in your garden is looking the worse for wear, you can take effective steps to renovate it. What you have to do will depend on the size of the problem you have, so the first step is to check out the symptoms and decide on a course of action. But there are a few basic techniques you can employ that will benefit any lawn.

  • Mow regularly At this time of year you should be cutting once a week. This will encourage fine-leafed grasses at the expense of coarser ones, and it will also discourage many annual and broad-leafed weeds.
  • Remove thatch Vigorously rake the lawn with a spring tine rake to remove dead bits of grass that collect at the base of the grass blades (known as thatch) and moss. This is very hard work, so unless your lawn is very small you may wish to buy or hire a powered lawn raker to do the job. The job is best done in spring or autumn, but if you are trying to renovate a lawn, you can have a go now.
  • Feed for growth Apply a granular lawn fertiliser that is high in nitrogen to encourage vigorous leafy growth. Apply when the grass is dry and the soil moist at the rate indicated in the manufacturer’s instructions. Try to apply just before rain is forecast so that the feed is
    washed in.
  • Control weeds Apply a selective weedkiller formulated for use on lawns any time the lawn weeds are growing actively and rain is forecast. Use a combined feed and weed treatment if you want to feed your lawn at the same time, or a feed, weed and mosskiller where moss is also prevalent. Always apply at the rate recommended by the manufacturer, reapplying if required to control persistent weeds.

Once the lawn is growing strongly, you can turn your attention to other problems.

Worn patches

If the lawn has been used as a shortcut from one part of the garden to another, the benefit of any renovation will be short-lived, so you might be better off putting in stepping stones or a path along this line. Areas that are worn out because of seasonal heavy use, such as garden games, are likely to have become compacted and will benefit from repair. The soil will be compressed with fewer air spaces, resulting in poor drainage and aeration. The simplest way to rectify the problem is to spike the affected area. On a small scale this can be achieved using a border fork – driving the tines into the ground to a depth of about 15cm (6in), and spacing the holes a couple of inches apart. This is tedious and time consuming, so for a larger lawn I would recommend that you consider hiring a powered lawn spiker or slitter instead. For best results, choose a machine that removes cores of soil rather than just pushing in solid tines. After spiking the compacted area, brush a well-drained soil mixture into the holes made from equal parts sharp sand and good garden soil.

Making repairs

Scratch the surface of the bare soil with a border fork or rake, incorporating a general organic fertilizer at the rate of 50g per square metre (2oz per square yard). Level and firm gently using the back of a rake before scattering grass seed at the rate of 20-35g per square metre (1 - 1 1/2oz per square yard). Cover the seed with a little sieved garden soil, water and then protect from birds by covering with twiggy pea sticks laid on the surface.

Bumps and hollows

An uneven surface can also result in bare patches – where the mower blades ‘scalp’ the high ground. Hollows, on the other hand, often show up as lush-looking areas where the grass can grow slightly longer than elsewhere on the lawn. Repairs are the same for both. For isolated high and low spots you can lift the turf and remove or add sieved topsoil or turf dressing as required to level the surface when the turf is re-laid. Use a sharp spade or half-moon edger to cut an ‘H’-shape with the middle over the bump or hollow. Undercut each side working from the central cut, so that the turf can be peeled back without cracking or tearing. Lightly fork over the exposed soil and add or remove soil as required. Level and firm before replacing the turf and fill any gaps with topsoil or turf dressing. For larger areas, you may be better off topdressing the whole lawn using sieved topsoil or turf dressing. Spread it evenly over the uneven patch not adding more than 1cm (1/2in) at a time as this will smother the grass. Do this a couple of times over the coming weeks and you’ll soon end up with a flat and easy to mow surface that looks good all summer.

Broken edges

Broken edges not only make the lawn and garden look a mess, but they also make mowing more difficult. If the edge is broken in just one or two places treat them in isolation. If the edges are generally ragged use a sharp spade or half-moon edging tool to re-cut them. Use a short plank as a guide for straight edges and a garden hose for curves. You may have to re-cut the edges once a year if you garden on light, sandy soils that crumble easily.

Making repairs

Use a sharp spade or half-moon edging iron to cut out a turf that incorporates the broken edge. Undercut the turf and turn it around 180 degrees, so that the broken edge is within the lawn and the straight edges aligns with lawn’s edge. Fill the broken area with sieved garden soil, level and re-seed, before covering with a little sieved garden soil, watering and protecting with twiggy pea sticks.

Poorly pulmonarias

Pulmonarias are very prone to mildew attacks (especially if the soil is dry) that can leave the plant looking very sorry for itself at this time of the year. Rather than trying to control the disease with fungicides, simply cut off all the foliage back to ground level, now that they’ve finished flowering. Then water and apply a general-purpose feed. Within a few weeks, a mound of fresh new foliage will be produced that is completely disease free. The narrow-leafed types are less responsive to cutting back so settle for watering and feeding them instead.

PROPAGATING ON A BUDGET

You don’t need a lot of expensive equipment to propagate most garden plants. In fact many shrubs can be increased from cuttings taken now and rooted direct in the garden. All you need is a home-made mini-tunnel constructed from an old polythene supermarket carrier bag and a few wire coat hangers. Simply prepare an area about the width of the polythene bag in a secluded, partially shaded part of the garden by thoroughly digging and removing weeds and debris. Improve the soil by adding plenty of compost as well as sharp sand to improve drainage. If your soil is poor, dig out a shallow trench and fill it with cutting compost instead. Most shrubs can be propagated either by nodal or basal cuttings. Nodal cuttings are trimmed just below a leaf joint with the lower leaves removed. Basal cuttings are removed from the plant by cutting through the swelling at the base of the shoot where it joins a woody shoot.

Insert cuttings into the prepared bed, water well, then cover with the polythene held up by the wire coat hangers. Cover the one edge of the polythene with soil and weigh down the others with bricks to keep it in place. Check periodically and remove any cuttings that are showing signs of rot. Water again if necessary. Within a couple of months the majority of the cuttings will have rooted and be ready for potting up individually. This is a very economical way of getting a lot of one type of plant, for groundcover or if you are planning a new hedge, but can also be used to raise plants for charity plant stalls and school fairs.

Summer cuttings to try

Azalea (nodal for evergreen types, basal for deciduous)
Berberis (basal or nodal cuttings)
Buddleja (nodal cuttings)
Callicarpa (nodal cuttings)
Ceratotigma (basal cuttings)
Colutea (basal cuttings)
Escallonia (basal cuttings)
Fatsia (nodal cuttings)
Forsythia (basal cuttings)
Hibiscus (nodal cuttings)
Hydrangea (nodal cuttings)
Hypericum (nodal cuttings)
Indigofera (nodal cuttings)
Lavatera (basal cuttings)
Ligustrum (nodal cuttings)
Lippia (basal cuttings)
Lonicera nitida (basal cuttings)
Pernettya (basal cuttings)
Philadelphus (nodal cuttings)
Spiraea (nodal cuttings)

Happy gardening!