For a fragrant display in late winter, sow sweet pea seeds
Contributing garden editor Marianne Alexander’s handy checklist of essential chores to do in March:
Pull out tatty summer annuals and add to the compost heap. Prepare empty beds for spring annuals and bulbs by loosening the soil to a depth of 30cm, turning in compost, superphosphate, (a good fistful to each square metre) and a sprinkle of hoof and horn (slow- release nitrogen) and bonemeal (phosphate).
Start cutting the lawn shorter as temperatures drop and the days shorten at the end of the month. Feed with 2:3:4 or 3:1:5 fertiliser. If your lawn was infested with winter grass (Poa annua) last year, spray with Kerb, a pre-emergence seed inhibitor.
Sow sweet pea seeds in deeply dug, well-composted beds, trenches or containers, and for faster germination, soak them overnight beforehand. In cold frosty areas, plant seeds in May or June to prevent the blooms being frosted.
Prune bougainvillaeas once their summer flush has faded. Rather than cutting back the branches, clip lightly giving them an all-over shear to remove all the old flower stalks. Feed with a high-potash fertiliser like 3:1:5.
Save seeds of cleome, cosmos, marigolds, zinnias, Queen Anne’s lace, fennel, lavatera and Verbascum. Dry store them in labelled envelopes or brown paper bags.
Buy spring bulbs as soon as they’re available. Towards the middle of the month, plant out indigenous bulbs, like babianas, freesias, ixias and sparaxis.
Plant lachenalias in pots as they dislike damp feet. Store exotic bulbs like bluebells, grape hyacinths, daffodils, anemone and ranunculus, which prefer cool conditions, in a cool, dark dry place until April. Divide overgrown clumps of the river lily, Hesperantha coccinea.
While they are still in blossom, tag summer bulbs like dahlias and gladiolus using an indelible waterproof pencil. Place stakes in the ground to indicate the position of deciduous perennials like hostas, astilbes, peonies, balloon flowers, fire lilies, Eucomis spp. (pineapple lily), perennial phlox and alstroemeria (Inca lilies) so that you don’t dig them up by accident.
Fill gaps and replace poor-performing shrubs with new, more suitable plants while the soil is still warm. In dry and drought areas only do this if you can provide enough water for them. Choose strong-growing plants in bags or pots that are in proportion to the size of the plant with no roots growing through the drainage holes.
Control weeds by pulling out those in flower beds and borders by hand. Pour boiling water or vinegar on weeds in paving or drizzle them with a little salt; if they’re persistent, ask your nurseryman for an herbicide.
Feed roses with a high-potassium fertiliser like 3:1:5 or 2:3:4 to harden them for winter in cold frosty areas. In other areas, give the last feed of 5:1:5 or 8:1:5 granular fertiliser. Spray preventatively for fungal diseases like black spot, mildew and rust, particularly in winter- rainfall areas.
The veggie garden
Strawberries are producing runners I on which new plants develop. Cut some off to reduce stress on the mother plant. Prepare a new bed for the offspring by digging in bonemeal and plenty of compost.
Start sowing winter vegetable seeds of beetroot, carrot, broccoli, cabbage, cauliflower, celery, lettuce, mixed salad greens, radishes, peas, spinach and Swiss chard and herbs like coriander, rocket and parsley.
Plant seedlings of broccoli, cabbage, cauliflower, kale, celery, leeks, lettuce and spinach.
Feed established vegetables once a month.
Feed all brassica seedlings with a balanced organic fertiliser like Vita-Green 5:1:5.
In the subtropics, continue planting warm weather crops like beans, beetroot, capsicums (above), courgettes, cucumbers, eggplants, lettuce, marrows and tomatoes.
Feed grape vines with 2:3:2 and granadilla and guava with 3:1:5.