Spring arrives officially this month, on March 21st, and by then the garden will be well on the way to a new season. The earliest shrubs will have started to bloom, Mahonia japonica with its bright yellow spikes of strongly scented flowers, the mezereon (Daphne mezereum), equally strongly scented but purplish-pink in flower, camellias, japonica, and that curious but attractively flowered shrub, Corylopsis spicata, in pale yellow, and acid-soil loving. These and other shrubs can be given a fertilizer dressing this month, watered in if the soil is dry; so, too, can herbaceous perennials, making the dressing relatively high in potash content if flowering is not all it might be. Rooted layers from shrubs can be detached and put in their permanent positions. Division of the border plants can also be undertaken successfully. Rose pruning will be in full swing; clematis pruning started last month should be finished by the middle of this one. Evergreens can be planted this month, watered in well at the time of planting, and put in when the soil is moist. If in a windy position, give a temporary shelter of sacking, or polythene, while they establish, as wind is one of the main causes of browning of foliage, particularly conifers. Moisture vapour is literally blown off the surface of the leaf, and the roots do not replace this until they take hold of the soil. If dry weather follows planting, spraying overhead with a drenching spray of clear water once or twice a day will do much to mitigate the effects of desiccation.
Lawns can be given a spring clean, by first raking (provided there is no moss), then topping with razor-sharp mower blades, and following with spiking and the first feed. Where there is moss, spring is a good time to treat it with lawn sand, but a more long-lasting remedy is to improve the soil drainage or plant food content, so that the grass always grows strongly.
Lots of annuals can be grown out of doors, but do not be tempted too early in the month, and in cold gardens next month will be soon enough. Three or four very warm, sunny days often occur in March, deceiving one into thinking summer is on the way, but are followed by cold wet weather, when seeds rot in the ground. Annuals sown in patches, with some thought to colour blending, are highly satisfactory; for instance; one might have all the blues, purples, lavenders and pinks together; or a patch of different shades of yellow.
The corms and tubers started into growth last month in the greenhouse will be ready for potting; da Infos can have cuttings taken from them. Rooted chrysanthemum and carnation cuttings will need potting in 3-in. pots; pelargoniums rooted from autumn cuttings will be growing and may need potting on. All sorts of pot plants can be turned out of their pots, the old compost removed, and replaced with fresh or, if they do not like root disturbance, the top I1 in. can be scraped off and replaced with a topdressing.
Last month’s seed sowings will need pricking out into boxes 2 in. apart each way – the plastic seed trays seem to give earlier and stronger growth. If the seedlings can be moved with the rounded root tip intact, they will ‘take’ practically without a check – try not to leave them too long in the seed-boxes. Once past a certain stage in their growth, even if pricked out they will never make good plants-they should be moved as soon as they are large enough to handle.
Tomatoes sown last month can be pricked out when the first true leaf shows, burying the stem so that the seed leaves are just above the soil surface. They will need warmth of at least 50°F (10 C) to keep them growing on; a check to growth either by cold or drought is disastrous at this stage, or when they are young plants. The sweet peas sown last month can be hardened off and planted out at the end of the month.
If alpine plants occupy a large part of the greenhouse, this and next month will be their hour of glory. A sunny, airy alpine house in the spring can be most colourful, and alpine plant cultivation one of the most satisfying and rewarding occupations. It needs a good deal of experience in gardening, on the whole; very well-drained composts are essential, and constant attention for most of the year. Small plants like these will be examined closely and need to be in first-class growth and flowering to be effective, so attention to detail is another ‘must’. Some of the most easily grown and colourful plants for alpine houses, blooming in spring, are: the miniature narcissi, tulip species, scillas, Aquilegia caerulea, Cyclamen orbiculatum, Anemone apennina, grape hyacinths, primulas in variety, Pulsatolla vulgaris (the Pasque flower), iberis, Gentsana acaulis, and Ramonda pyrenaica.
In some parts of the country it is possible to sow seeds of herbs out of doors this month, but if the garden is a chilly one or the soil heavy, it is better to sow in the greenhouse. Parsley is always said to be slow to germinate, but in warm soil it comes up just as quickly as the other herbs, and an out-of-doors sowing of it in April will produce more plants in the long run than a March one. Dill, coriander, sorrel, chives, sage, sweet marjoram and summer savory all germinate easily.
Parsnip can be sown in early March; it is very hardy and needs a good long season to develop. Most of the rest of the vegetables, summer spinach, broccoli, spinach beet, sprouts, cabbage, cauliflower, early carrots, leeks, onions, lettuce, peas, radish and spinach beet can be sown outside later this month. Celery, celeraic, cucumbers, melons and more tomatoes can be sown in heat.
Preparation of the soil for seed sowing will be the same as for annuals, broken down and raked to a crumb structure, and fed about to days before sowing. Seed is sown when conditions are moist, as warm as possible and preferably when rain is expected. Lining the drills with moist peat, or sieved compost helps germination and subsequent growth in difficult soils and poor weather. Maincrop potatoes should be put to sprout.
From vegetables to fruit-the earliest to break dormancy will be the blackcurrants, and they may need spraying before the end of the month if the greenfly hatch is early; malathion, derris, dimethoate or menazon are suitable controls. Bud pecking of gooseberries and blackcurrants must still be watched for, as it is easy to lose an entire potential crop at this stage as a result of bullfinch attacks. Cane spot of raspberries is a particularly deadly fungus disease, which reduces production of new growth, and depletes fruiting of the lIder canes. Spray with lime sulphur or captan to control this, if present, as the canes begin to shoot. Uncloched strawberries should be cleared of dead leaves, accumulated during winter.