March gardening guide: what to do in your garden this March
March is the first month of spring, and gardens are coming alive with the colour of spring bulbs. In flower are Crocus, Daffodils, scented Narcissus, Fritillaria meleagris (common name ‘Snakes Head Fritillary’) and the delicate Erythronium.
Gardening calendars are only a guide because so much depends on the weather in March. Sometimes it can be spring-like, other times cold and frosty. The weather will affect the degree to which the soil has warmed up, ready for planting.
March gardening guide: Planting
Books and magazines are full of ideas for plants to buy and plant out in March. But in many parts of the country, March can be a cold month with frosts; we will never forget the beast from the east. March is not the time to plant frost tender plants as just one frost can kill the tender plants. However, you can start sowing as the days get warmer and the level of light increases.
If you are making an early start, a greenhouse, sunny porch or under glass is ideal for germinating seeds, establishing containers such as hanging baskets and bedding ready for later in the year and starting vegetables. All will need to be ‘hardened off’, which means gradually getting them accustomed to the harsher outside weather before planting out.
Plant herbaceous flowering plants
Dahlias are a lovely showy garden plant if you have the right growing conditions. Dahlia does best when grown in well-drained soil and in sheltered warmer conditions, which means they thrive and produce better blooms in Southern counties. Dahlias will grow in more exposed gardens, but they will need protection from frost.
If you buy Dahlias as tubers, you need to plant about 6 weeks before the last expected frosts. Dahlias are not frost-hardy, and any frost will damage the new top growth. It takes about 6 weeks for the new growth to come through, hence the time delay. If you get caught out, cloche them. If the growing conditions are not ideal, such as colder and wetter, it is better to start Dahlias in containers under glass and bring them out to harden off in May.
Lilies look fantastic in summer borders. Many Lilies are tall, often scented and make good patio plants. March is the right time to get the bulbs going in pots, and it is much cheaper than buying them as more mature plants later in the year. Pick good-sized pots, fill them with suitable compost, plant 3 bulbs per pot, and then cover in more compost.
Keep the bulbs in a sheltered spot or in the greenhouse until established. The pots are ideal for placing on the patio to enjoy the scent or filling-up gaps in borders.
The advantage of sowing annuals from seed is that you can choose from a wide range of varieties and colours. This enables you to grow plants which you rarely see in the garden centre. It’s fun to grow something unusual. An exotic annual to grow is Ipomoea, also called Morning Glory, which produces delicate and attractive trumpet-shaped flowers.
Now is the time if you’re thinking of growing Sweet Peas from seed, although they need plenty of time and effort. In March, you can sow sweet peas under glass or directly where they are to grow outside if it is a more sheltered area.
Plants and shrubs in containers
Many plants and shrubs are ideal for growing in containers on a permanent basis. Over time, the compost can become depleted. One way to remedy this is to apply a feed, and the other is to topdress the container in the spring. To do this, simply remove the top 5cm to 7cm of compost in the container and top it up with fresh compost, which will improve the soil.
All containers are prone to drying out more quickly; applying a mulch may help to reduce water loss. And there’s no need to waste the compost you remove. Spent compost makes an ideal mulch and comes in handy for topping up soil levels in borders.
Plant snowdrops for next year
If you enjoyed an inspiring snowdrop walk this winter, March is the time to plant snowdrops. The easiest way to establish snowdrops is if planted ‘in the green’, which is as miniature plants, not bulbs.
It can be harder to get snowdrops established from bulbs, so better to buy plants now and plant in clumps. Snowdrops are a woodland plant, which means they dislike too much sun and are best planted in an area that gets some shade; close to or under a shrub always looks nice.
March gardening guide: Care and maintenance
In March, you can tidy up perennials and cut them back before the new growth gets too advanced. Once the plant has started regrowing in earnest, it can be near impossible to cut back without damaging the growth.
Prune Bush and Shrub Roses. First, remove anything that looks unhealthy. This includes any branches that are spindly or don’t look good. Then look at each significant remaining one, find a bud that faces outwards (away from the plant), and cut on a slope just above it. Cut to around knee-high (40cm or 1ft to 1.5ft). You are aiming for a goblet shape. It’s a good idea, if you have time, to feed the roses after pruning.
March is also the correct time to prune Buddleia if you haven’t already done so. Cut back to 15cm. Don’t panic as it will look very bare. Buddleia is a vigorous shrub and will quickly regrow. Check your variety of Buddleia. March is time to prune B. davidii but not Buddleia alternifolia or Buddleia globosa. This is because these Buddleia have flowers on last year’s stems (called old wood,) and if you prune now, you’ll cut off the flowers.
You can also hard prune Lavatera, as the new green shoots are emerging, cut the old wood right back, and the new growth will flourish and carry this year’s flowers. Prune Coppice Eucalyptus to keep it under control. And prune Hydrangea paniculata by removing its spent flower heads and cutting it down to a bud. Prune winter-flowering Jasmine by removing most of the weak straggly and spindly growth.
Give Cotinus either a light prune to trim it into shape or a hard prune to contain growth. As for Lonicera (Honeysuckle), prune about one-third of the oldest growth down to ground level. If the plant is overgrown, it can be pruned hard to rejuvenate. Prune Pyracantha (firethorn) and Euonymus lightly; trimmed back into shape and to keep to size. This is also the last chance to prune Wisteria, which is essential to keep it flowering.
March is time to cut back Cornus (common name Dogwood) if you want colourful stems next winter. Cut down close to ground level. This will encourage the plant to shoot and grow new ones, which will provide next winter’s colour. You can cut all or most of the stems. If they are not cut down over time, the colour will lessen.
Assess spring bulbs and daffodils
This is the time to assess the performance of spring bulbs, especially daffodils. If you have a clump of daffodils that are blind, that is to say, without flowers, mark them with a stick for attention. Once the foliage is going over, lift the clump and check them. If they are congested, plant back, having first separated the bulbs and plant further apart.
As the early daffodils finish flowering, deadhead them, but it’s crucial to leave the foliage in situ until it has died back. This feeds the bulb for next year. And you can give the fading bulbs a feed as well. Another common cause of blind bulbs is if they are planted too shallow. Ensure when replanting the clump, it is at least 3 times the depth of the bulb.
March gardening guide: Wildlife and pests
Watch out for slugs
As the soil warms up, so do the slugs. Emerging delicate shoots of herbaceous plants, such as Hosta, Delphinium and lupins, are the tastiest snack for a slug. Start protecting the plants.
March gardening guide: Other garden tasks for March
Prepare the vegetable plot
March is the month when planting gets underway. But before planting, it is worth spending time to improve the soil. Most vegetables are hungry feeders, and it’s a good idea to enrich the soil with organic matter such as well-rotted manure, chicken pellets, or compost.
Digging the soil and mixing-in organic material will break it up, ensuring it is not compacted, and prepare it for the growing season. However, if it’s very wet or has been a wet winter, it’s more important to keep off, to not compact the soil.
Many crops such as salads and carrots like fine soil, making stones a hindrance. Raking the plot to render the soil finer makes it easier to plant into and creates a better growing medium.
Whether you’re growing your vegetables from seed or small veg plants, deciding when to plant out in the vegetable plot depends on the vegetable, the weather, and your location.
The hardiest of the Bean family is Broad beans which means they can be planted out first. In March, you can sow outside if the soil is warm enough, but you will need to protect new growth from a heavy frost or snow by a fleece or cloche. An alternative if you have a conservatory, greenhouse, or cold frame, is to sow seeds under glass, so you have sturdy plants to put into the vegetable plot later in the spring.
In March, it is best to plant only hardy vegetables outside. The same applies if you are buying small vegetable plants, they will need protection from the worst of the weather. Small plug plants are of good value but are grown in ideal conditions, protected from the weather. After purchasing, you will need to do the same.
All beans like a long root run and are best germinated into root trainers or loo rolls holders; sow the seeds nearer the top of the holder, so the roots can reach down. The same is true if you are sowing sweet peas. Beans need no attention whilst growing, other than to ensure light levels are good so that plants do not get spindly. Water carefully if in loo rolls holders, only in the centre. Try not to water the cardboard holder as it will disintegrate.
If your plot is exposed/subject to frosts and cold winds, even with cloches and protection available, it is best to delay outside sowing of French beans, cucumbers and squashes until later April/May. You can sow these under glass and start off young plants. It is better to wait for later in the season for sowing or planting outside.
This month you can either carry on chitting potatoes or plant early ones. Potatoes are an easy and rewarding crop to grow. And chitting or sprouting potatoes is a fun activity to do. It is simply the process of forcing seed potatoes into growth before they are planted out.
Potatoes can take up a lot of space in the vegetable plot, but fortunately, they are ideally suited to growing in containers. If you have a greenhouse, you can even start potatoes off in containers in the greenhouse and move out once all risk of frost has passed. Frost will damage the new potato shoots, called haulms. The time growing in the greenhouse will get the plants off to a good start.
Indoors or in a greenhouse, March is an opportunity to germinate herbs, such as Basil, Dill, Parsley, Chives and Coriander. Tender herbs such as Basil and Coriander will need to be kept warm and frost-free until later in the year and are best not planted out until May.
Parsley can be seeded where it’s to be grown, whether in the vegetable plot or containers. It can be tricky to germinate and needs some warmth, so early seeding can be slow. Parsley needs to be kept moist. And if you fancy growing something different, Thai Basil is widely available. It is easy to grow and great in stir-fries; it has a distinct aniseed flavour to the leaves. Start off under glass, the same as Basil.
Chives are hardy and will live in the garden all year round. In March, you can see the shoots growing again. There is a variety of garlic chives, called allium tuberosum (common name Chinese chives), with a mild garlic flavour. Like all chives, it is easy to grow, and it flowers white during the summer. Bees love Chives.