Garden Jottings: March

Christine Brown

President, AHS.

We have had rain on nearly every day this year with only one or two short glimpses if the sun to give hope of Spring days to come. Celandines are in evidence among the muddy sodden stream edges and there are hundred of catkins of all varieties along roadsides and hedgerows. Mimosa, camellia and sarocca are showing the beneficial effects of plentiful water to give rise to beautiful blossoms and perfume in the air.

Most shrubs will have been shortened by about one-third in the Autumn but will need the main pruning completed. There can be a risk that cold frosty weather will damage hard pruned plants if carried out too early, so be aware. Make sure to have some sturdy gloves a well sharpened and oiled secateurs and loppers at the ready. Rose bushes will become tall and lanky without pruning and become unattractive. Pruning keeps their size in check and allows better air circulation preventing fungal infections such as black spot.  Removing older wood encourages the growth of new stems full of vigour to produce more good blooms. The best time to prune is now: from late winter to March.

For all types of roses begin by removing dead, weak, spindly or crossing stems. Hybrid teas – those bearing single larger blooms on one stem – should be cut back to 15 cm (6 in).  Floribundas – which hold their flowers in clusters – should be cut back to 30 cm (12 in). Old-fashioned shrub roses – which make large plants – should be reduced by one-third to maintain the shape of their large bushes. Rambling roses are best pruned in August after flowering, and climbing roses during winter months into March. All roses should be pruned down to an outward facing bud maintaining a nice open shape, to encourage new growth from the base. Climbers should be grown horizontally if possible, as more flowering shoots will break out from stems grown in this way. It is possible to train vigorous varieties up into trees or around a study post, obelisk or pergola, possibly twisting and twining around the support to encourage flowering shoots. Tie the growth securely the supporting structure, even a shed or arbour.

Later in the month buddleia and clematis can be tackled. Buddleia can be cut down to 45cm, removing a few old stems. Clematis in Group 2 – The President or Nellie Moser, for example – should be trimmed down to 45 cm, taking out damaged and broken stems down to a pair of healthy buds. Group 3 – late flowering varieties such as Perle d’Azure and Jackmannii – cut down to 15-30 cm (6-12 in) above soil level and overwintered fuchsia cut right down to a good bud near the base.  All shrubs should be fed and roses sprayed against disease and aphid infestation. Now is the time to remove spent flower heads kept to protect the emerging buds on hydrangeas. Cut stems back to a pair of nice fat buds. If none are apparent remove the whole stem and any other weak or dead ones if the cold weather has passed. 

Late March is the time to clip over grey-leaved shrubs: sage, santolina, phlomis and curry plants. Firm all shrubs and plants into the soil to prevent wind rock and the formation of water and ice damaging roots where a hole has formed around the stem. A mulch is beneficial for all woody plants, but do not heap up around the stems or it will rot them. 

Annuals can be grown in a greenhouse, conservatory or on a windowsill giving as much light as possible, to avoid tall spindly plants. When a second pair of leaves appears, plant them in section in trays, handled by their leaves not their stems. As they get larger, pinch the tops out to encourage bushy, sturdy plants. Cuttings can be potted up now, and overwintered plants watered more often and fed. 

Early potatoes should be planted, by tradition, on Easter Monday; a little compost can be added to rows. It is possible to plant seed potatoes without preparation, and they will grow, but it is still best to choose potatoes with ‘eyes’. These should have been chatted (put in a light place to shoot) last month and have short sturdy eyes or shoots. Place them in the base of the trench, shoots uppermost, 30 cm (12 in) apart. Early salad varieties are good for a small plot, as you can’t beat new potatoes fresh form the garden. 

Onions should be planted 15 cm (6 in) apart in rows on a well firmed soil bed to which some fertiliser e.g. Growmore – is raked in the surface. Garlic can also be grown in this way. Trim any long ends of the sets (small bulbs) before firming them into the ground, or blackbirds will think they are nesting material and pull them up. It is a good idea to cover the bed with wire mesh or net to discourage them until the sets are well rooted.

Sow seeds of sprouts, cabbage or purple sprouting broccoli indoors. If broad beans sown in Autumn have not flourished sow some more in situ, as they will germinate even in low temperatures. Carrots can also be sown outside now. Seedling tomatoes will need to be potted into 8cm (3 in) pots. Lettuce could be grown on into modules. Winter varieties can be grown outside if hardened off well before moving out. Strawberries should be tidied up and new plants or ‘runners’ you have propagated put into a bed with plenty of well-rotted humus (compost or manure) dug into the soil.

Look for emerging shoots of lupins, delphiniums and chrysanthemums which can be taken to propagate new plants, which will be the same colour and variety as the parent plant. Place the shoots (cut with a sharp knife) just below the soil with a little of the root attached into small pots of well-draining soil consisting of sharp sand, grit and compost. Set them around the sides of the pots as they will root faster here.

Keep watering cans filled up in the greenhouse to avoid filling from the water butt, as the cold will shock plants. Keep an eye on temperatures in the greenhouse as is this a tricky time with hopefully bright days but cold nights, so try to air the greenhouse carefully according to the weather occurring daily. 

This is the start of the busy growing season and if the list I have given seems arduous, with lengthening days and doing little and often the tasks will bring rich rewards – happy days.