Spring clean
Now that the drab days are behind us, sprucing up the garden becomes more appealing. Some simple tasks really lift the garden; sweep and weed paths and patios, hoe gravel and rake out weeds on dry windy days, and top up gravel, wood chips and bark on paths.
Cutting lawn edges makes a particularly telling improvement. Use a plank or string to guide the straight edges. Then remove weeds and lower the soil level next to the grass. Fork over bare bits and reseed or use the pieces of grass from cutting edges. Press these “divots” into the soft ground a few centimetres apart and water well. They should soon root and knit together.
Winter grime on garden furniture and equipment responds to suitable cleaners. Leave algae, mosses and lichens on other surfaces, though, including tree trunks and the soil – these natural coverings support wildlife and do no harm.
Pond algae often responds to barley or lavender straw placed in the water now. As it rots, it releases hydrogen peroxide that can prevent algae from making the water turbid.
Lawn care
Lawns start into growth early compared with most plants, and light, frequent mowing is better than one severe mow later. Where the grass is tall, cut in increments, remove no more than 5cm at a time to avoid stressing the grass, which will reduce sward quality. Frequent mowing also allows the clippings to fall into the sward and act as fertiliser.
The bright, warm, dry spring so far has meant there is less need for fertiliser than usual, with grass growing well on its own. Reassess growth and greenness when wet weather is forecast – if needed, a lawn fertiliser will act swiftly.
Moss is often present in lawns and a good remedy is to rake out the worst and treat with a biological moss control product. These work well as spring weather warms. These also act as a mild, slow-acting fertiliser, keeping the lawn green with no further inputs.
While lawn weeds cannot be tolerated on fine turf, most gardeners prefer an easy-to-care-for “all round” lawn where some weeds don’t detract from the effect. In fact, the lawn is easier to live with – providing a robust, smooth surface. For new lawns, choose a mixture of tough, hard-wearing ryegrass and creeping fescues that knit the sward together. If possible, for the sake of garden wildlife, leave some – even if only a couple of square metres – unmown. Grasses will grow tall and flower, followed by seeds eaten by birds. Weeds will also flower and seed. Caterpillars and other insects often feed on the taller grass. This “meadow” is only mown in later summer when all the seeds have been shed
Wildflower meadow
Where permanent meadow is wanted, add to the flowers such as daisies already present in lawns by inserting plug-raised wildflowers such as cowslips and harebells. If the site suits them, they will flower and spread of their own accord.
If starting a wildflower meadow on a new site, use a mix of wildflower seeds formulated to suit the soil.
Cornfield wildflowers are annuals, such as cornflower, corn chamomile, corn marigold, field forget-me-not and common poppy, which can be broadcast thinly on bare soil now and raked to cover. Press the soil with the head of a rake or tread to ensure good seed-to-soil contact so moisture is taken up by the seed. Water and allow to drain before sowing.
Many garden annuals are cornfield species but often come from cornfields in other countries, so are not exclusively native species. They are less useful for biodiversity than natives, but they still make attractive pollinator-friendly displays.
Typical species include larkspur, love-in-a-mist, cornflower, California poppy, Coreopsis tinctoria, Gypsophila elegans, toadflax, Shirley poppy and Phacelia tanacetifolia.
Birds and insects
Insects become active as the weather warms, with many feeding on flowers. Consider planting extra insect-friendly spring flowers if your garden is light on them: aubrieta, flowering currants, grape hyacinths, honesty and Japanese quince can find a place in most gardens.
Where possible, allow spent winter vegetables (such as kale and sprouting broccoli) to flower – their bright yellow flowers are rich in pollen and nectar.
Leek flowers are valuable too. Some spring-flowering weeds – dandelions, lawn daisies and red deadnettle – are also relished by pollinators. Spare these for as long as possible.
Some aphids and caterpillars may appear on trees and bushes. These do no significant damage to ornamental plants and are eaten by birds. Some action may be needed if apples are seriously affected, however.
Birds are nesting at the moment and nearby water will help them. Clean bird baths and other water sources every week to reduce chances of them carrying diseases. Clean and move feeders/feeding stations to avoid detritus build-up which may harbour disease. Providing a patch of wet muddy ground will help birds and insects building nests.
Pots & baskets
Patios, paved gardens and balconies need striking plants. This can be provided by “seasonal” plants, which fill garden centres in April. Plant these outdoors after the risk of frost has lifted to flower until autumn frosts. Spring can be treacherous, so be ready to cover with some fabric if a cold night threatens.
Tender angelonia, calibrachoa and petunias are inexpensive and flower on and on, and are an easy choice to fill a tub or basket under almost any sunny conditions. They can broil on a sunny patio unless watered several times a day, so consider even more drought-tolerant choices such as osteospermums, pelargoniums, salvias and, for a less usual choice, scaevola with its lobelia-like flowers.
South African daisies – arctotis, felicia and gazania – are a vibrant choice but only where full sun is guaranteed – their flowers close up in shade.
Where frosts still linger, or for colder regions, consider antirrhinum, bedding dianthus, brigeron and armeria, a form of seathrift, which flower well all summer and don’t go pale and sickly if the nights turn chilly.
Dahlias are the mainstay of seasonal planting. They flower reliably, come in a good range of colours and shapes, and the tubers can be kept for next year. They need moist, fertile soil with good sun. Canna need similar treatment and offer sword-like leaves as well as bright flowers.
For shade, impatiens and fuchsias are common and effective choices, but it asks much for plants to grow much in shade, so plant closely.
Gardeners are sometimes intimidated by colour and are uncertain when mixing plants – containers of all one plant always look good and avoid doubt.
Elsewhere, adding plenty of foliage interest and white flowers often softens plantings. Perhaps a blue theme, with the fragrant foliage of verbena, lightly scented nemisia both in blue/purple, softened with some grey cineraria and white bacopa.
But in the end, your garden is your own affair – so be bold if you wish.
Sow more veg
Soils are warm in April, but might be dry after no rain in March. Where soils seem dry, water the day before sowing to make sure there is enough moisture for seeds to germinate.
All the hardy vegetables and herbs can be sown in April – beetroot, broad beans, cabbage family plants, carrots, chard, coriander, dill, kohlrabi, leeks, lettuce, onions, parsley, parsnips, peas, radish, spinach and turnips. Potatoes can be planted now, but be ready to cover tender shoots if frost threatens. In warm regions and light soils, French beans and sweetcorn can be sown outside but elsewhere sow in cell trays or small pots indoors.
Cucumber family plants –courgettes, squash and pumpkins – can be sown indoors now, unless it is more convenient to wait until early June to sow outside. The same applies to runner beans.
New trees & shrubs
Trees, shrubs, climbers and fruit planted over winter will be at risk of drying out in sunny and windy weather –especially evergreen plants. Watering to keep the root ball moist will prevent losses.
Trees planted in the past two years need careful watering even in rainy summers, but after three years will have enough root to survive dry periods.
New woody plants planted from now on will need careful attention, as they will be very vulnerable. Water them well before planting, take out a planting hole and fill this with water, planting once the water has drained away.
Getting water to soak deep enough into the soil around new trees and shrubs can be tedious with a hose or watering can. Watering bags (below) allow steady seepage into the root zone.
Cherry family trees (prunus) are should be to silver leaf disease and are pruned from April until July when infection risks are lower. Prune large spring-flowering shrubs once flowering is finished.
Plant more flowers
Garden centres are full of flowers in April, but it is also a good time to divide plants in your own garden, especially those that grow new roots in spring such as agapanthus. Water well beforehand, then lift and prise the clump apart or cut with a knife. Replant strong sections from the edge of the clump, discarding the rest.
The advantage of garden centre plants is that they are offered in flower, so choosing colours is straightforward.
Less usual plants are available at shows/plant fairs from now on. If you want to wait and buy later, rake in some annual flower seeds (brachyscome, inset, or calendula, for example) to exclude weeds and add some colour.
Other valuable quick-growing flowers to sow indoors now include cosmos (far right), sunflowers and zinnia (right). They can be sown outside next month.
More plantings of dahlias, gladioli and other summer-flowering bulbs into warmer April soils will add further summer flowers.
Houseplant care
It is still a bit cold to put houseplants out in the garden to get more light and humidity, but it is a good time to prepare them by repotting and feeding every fortnight as light levels rise and central heating no longer dries out the air.
They will need more water but beware of overwatering. Keep them moist but not soggy and check them frequently.
Sunny window sills and conservatories could bake many houseplants, especially lush green ones like philodendrons, so shift to shadier places to avoid overheating.
Populate hotter places with succulents and cacti – but remember that all plants have their limits and a sunny window sill in summer might not suit any plants.
It is a good time to propagate houseplants, too. Cuttings taken now will be rooted and ready to pot by June and have the whole summer to grow and become robust enough to survive winter.
Beds and border
The last of the winter debris can be cleared and the ground hoed to eliminate weeds and make conditions inhospitable for slugs. Slugs are on the back foot, so to speak, after a dry spring. Spread fertiliser such as blood, fish and bone before hoeing if the plants are not doing well.
Growth will surge next month. Staking and supporting is much easier if stakes and other supports are already in place, rather than trying to support growth that has already flopped.
Taller canes, bean poles and stakes can be used to make tepees to support climbers.
Clematis in 9cm pots are a tempting buy for late-summer flowers; sweet peas planted now are a traditional choice; scarlet runner beans sown next month can offer masses of flowers.
Tender climbers such as black eyed Susan (thunbergia) and rhodochiton with pendulous, maroon tubular flowers are good choices for warmer gardens.
Prune less hardy shrubs and subshrubs such as lavender, penstemon, phlomis, rosemary, sage and santolina before growth starts but after the worst of the frosts. Fresh shoots that will later bear flowers should result.
