What to do in the garden in March

early flowering Clematis

March at a Glance

  1. Plant summer bulbs, such as Dahlia and Lily
  2. Pruning month: Roses, Buddleia, Cornus, Hydrangea and more
  3. Plant snowdrops for next year's display
  4. Prepare the veg plot
  5. Sow hardier seeds and half-hardy annuals under glass

March in the Garden

March is the first month of spring, and gardens are 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. For more information Check out shrubs and plants flowering in March 

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.

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 (check out 'frost tender') just one frost can kill tender plants.

However, with some warmer days and increasing light levels, you can start sowing. Ideas and a video about how to sow and germinate seeds. 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 veg. All will need to be "hardened off" which means gradually accustomed to the harsher outside weather, before planting out.

Looking to add some March colour to the garden? Check out shrubs and plants at their best and flowering in March.

What out for these!

As the soil warms up, so do the slugs. Emerging delicate shoots of the herbaceous plants, such as Hosta, Delphinium and lupins, are the tastiest snack for a slug. Start protecting the plants; tips on how to beat the slugs.

slug attack

  

Annotated image of Dahlia tuber showing which way up to plant

March and April is a good time to plant summer bulbs such as Dahlia and Lilies. If you have the right growing conditions, Dahlias are a great showy garden plant. 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 and to be lifted before the winter.

If you buy Dahlias as tubers, you need to plant about 6 weeks before the last expected frosts. This is because Dahlias are not frost hardy (explanation of frost hardy) and frost will damage the new top growth.

It takes about 6 weeks for the new growth to come through, which is the reason for the time delay. If you get caught out, cloche them.  If your growing conditions are not ideal, such as colder and wetter, it is better to start Dahlias in containers under glass and bring out to harden off in May. More tips about How to Grow Dahlias.

Where ever you plant Dahlia, the pointy end goes up. If you look at the image, you can see where last year's stem was, and this goes upright, and it's planted as per the image.

Lilies look fantastic in summer borders. The image above is Lilium Regale. Many Lilies are tall, often scented and make good patio plants. March is the right time to get the bulbs going in pots, which is much cheaper than buying as more mature plants later in the year. Pick a good-sized pot and fill with suitable compost, plant 3 bulbs per pot, and cover with 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 the borders. More about growing lilies and images of different types of Lilies.

Crocus has some wonderful bulb offers (affiliate link purchasing may generate commission to the Sunday Gardener,)including Dahlia, Lilies, Freesia, Gladioli, Hemerocallis and more.

 

 

sedum cut back

Tidy Perennials

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 difficult to cut back without damaging the this growth.

In the image, the Sedum has had all the old growth removed. 

 

 

Pruning Shrubs in March

The following shrubs can be pruned in March:

  1. Prune Bush and Shrub Roses. First, remove anything that looks unhealthy. This means removing any branches which are spindly, or don't look good, prune them away. Look at remaining framework on each major branch, look for a bud which faces outwards (away from the plant) cut on a slope just above. Cut to around 40cmc (1ft - 1.5ft) which is around knee high. You are aiming for a goblet shape. It's a good idea, if you have time, to feed the roses after pruning.
  2. If you haven't already done so, March is also the correct time to prune Buddleia. Cut back to 15cms don't panic as it will look very bare. Buddleia is a vigorous shrub and will quickly re grow. Check your variety of Buddleia. March is the time to prune B. davidii but not Buddleia alternifolia or Buddleia globosa. This is because these Buddleia have flowers which are on last year's stems (called old wood,) and if you prune now, you will cut off the flowers. (Images to show which is which.)
  3. 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.
  4. Coppice Eucalyptus to keep it under control.
  5. Prune Hydrangea paniculata removing the spent flower heads and cut down to a bud, more about growing and pruning Hydrangeas.
  6. Prune winter flowering Jasmine removing most of the weak, straggly and spindly growth. 
  7.  Give Cotinus either a light prune to trim into shape or a hard prune to contain growth.
  8. 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. 
  9. Prune Pyracantha (firethorn)  and Euonymus lightly trimmed back into shape and to keep to size.
  10. Last chance to prune Wisteria, which is essential to keep it flowering. Tips and video on how to prune Wisteria.

Pruning Cornus in March

March is the time to cut back Cornus, common name Dogwood if you want colourful stems next winter. Cut down close to ground level, which will encourage it to shoot and grow new stems 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.

Below, the first image shows two Cornus, an uncut Cornus, and a pruned Cornus together with a tug showing just how many stems need to be removed.

The second image may seem odd because it is a home-made propagator in which Cornus off cuts have been used to prop up the poly bag. Look closely and you will see it's not just the seedlings which are growing but also the Cornus twigs. Cornus must be one of the easiest shrubs on the planet to propagate. Cut, push into soil, and keep moist and up it grows. Ideal for the gardener and as gardening gifts, echo friendly, no air miles home grown. 

Also, the cut Cornus stems are useful as pea sticks to support small plants and seedings, such as the sweet peas bean family when they are growing under-glass before planting out. 

Plant snow drops for Next Year

If this winter you enjoyed an inspiring snow drop walk, March is the time to plant snowdrops. The easiest way to establish snowdrops is if they are planted "in the green" which is as small 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 which gets some shade close to or under a shrub always looks nice.

Scented Narcissus

Assess spring bulbs and daffodils

This is a good time to assess the performance of spring bulbs, especially daffodils. If you have a clump of daffodils which 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, dead head them but it's important to leave the foliage in situ until it has died back. This feeds the bulb for next year, plus 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 re planting the clump it is at least 3x the depth of the bulb. Check out Why don't spring bulbs flower? 

Acer growing in a container

Plants and shrubs in Containers

Many plants and shrubs are ideal grown in containers and 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 5-7cms 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.

No need to waste the compost you remove. Spent compost makes an ideal mulch and is useful for topping up soil levels in borders.

Sow annuals for a summer display

sweet peas

The advantage of sowing annuals from seed is that you can choose from a wide range of seeds 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. More tips and advice on growing Ipomoea 

If you are thinking of growing sweet peas from seed, now is the time to sow. Although Sweet Peas need quite a lot of time and effort, I cannot resist sweet peas and grow them every year. In March you can sow sweet peas under glass, or in more sheltered areas, directly where they are to grow outside. Video how to Plant and grow sweet peas.

March in the Veg plot

Prepare the veg plot

veg plot

March is the month when planting gets under way and before planting, it is worth spending time to improve the soil and raise yields. 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 up the soil, ensuring it is not compacted, and prepare it for the growing season. However, if it is very wet, or has been a wet winter, it is more important to keep off the soil so it doesn't get compacted.  Many crops such as salads and carrots like a fine soil and stones are a hindrance. Raking the plot to render the soil finer makes it easier to plant into and creates a better growing medium, as in the image.  

Cold weather protection

bean emerging

Whether you are growing your vegetables from seed or small veg plants, deciding when to plant out in the veg plot depends on the veg, the weather, and your plot. 

The hardiest of the Bean family are 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 seed and under glass so you have sturdy plants to put into the veg plot later in the Spring. In March it is best to plant outside only hardy vegetables.

  The same applies if you are buying small vegetable plants, they will need protection from the worst of the weather. Small plug plants are good value, but they 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 are best germinated into root trainers or loo rolls holders. Sow seed 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 on 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, but for outside sowing or planting out it is better to wait for later in the season.  

Chitting potatoes

Chitting potoatoes

 This month you can either carry on Chitting potatoes, or plant early Potatoes. Potatoes are an easy and rewarding crop to grow; for tips and advice. Potatoes can take up a lot of space in the veg plot so fortunately Potatoes are a vegetable 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.

Germinating herbs in March.

thai basil

  Indoors or in a greenhouse, March is also 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 is to grow, whether that is in the veg 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. 

 If you fancy growing something different, Thai Basil in the image is widely available. It is easy to grow and great in stir-fries. Start off under glass the same as Basil. It has a distinct aniseed flavour to the leaves.

Chives are hardy and will live in the garden all year round. In March you can see the shoots growing again. There is also a variety of garlic chives, allium tuberosum, common name Chinese chives which has a mild garlic flavour. Like all chives it is easy to grow and and flowers white during the summer. Bees love Chives.

last updated 01.11.2021