Ask a Garden Designer: What Do I Need to Do in the Garden in May?
May heralds the freshness of spring and the promise of summer – plus all that new growth is so uplifting for the soul
Many consider May to be the best month in the gardening calendar – a time when wonderful spring plants and bulbs suddenly emerge from dormancy and burst into life. Chelsea Flower Show, of course, is a major highlight this month, while out in the woods there’s a sea of bluebells, and gardens everywhere are showing signs of promise for the year ahead.
Boost your shady corners
Aquilegia (columbine) comes into flower between May and June (it can be planted between March and May) and prefers dappled shade. It’s such a pretty flower, either with a single or double form, and good for attracting bees, too. No garden should be without them and they will naturalise in a woodland setting.
Aquilegia are very good at self-seeding and can get into small cracks in paving, but that can create a very pretty effect. They look good against grasses, too, such as the soft, feathery Stipa tenuissima. Lovely varieties of Aquilegia include the double form ‘Nora Barlow’ (pictured) and, for a deeper colour, ‘Black Barlow’.
Aquilegia (columbine) comes into flower between May and June (it can be planted between March and May) and prefers dappled shade. It’s such a pretty flower, either with a single or double form, and good for attracting bees, too. No garden should be without them and they will naturalise in a woodland setting.
Aquilegia are very good at self-seeding and can get into small cracks in paving, but that can create a very pretty effect. They look good against grasses, too, such as the soft, feathery Stipa tenuissima. Lovely varieties of Aquilegia include the double form ‘Nora Barlow’ (pictured) and, for a deeper colour, ‘Black Barlow’.
Know your onions
Alliums are at their best in May and planting them in large drifts through the beds is wonderful. Being from the onion family, they like good drainage. They tend to have floppy leaves that hang and look a bit messy, so make sure you plant them among other perennials or shrubs for support.
A good, reliable variety is ‘Purple Sensation’. Plant them 10-15cm deep and the same measurement apart from each other. The larger varieties, such as ‘Globemaster’ and Cristophii should be planted 30cm apart due to the size of their heads when flowering.
Alliums are at their best in May and planting them in large drifts through the beds is wonderful. Being from the onion family, they like good drainage. They tend to have floppy leaves that hang and look a bit messy, so make sure you plant them among other perennials or shrubs for support.
A good, reliable variety is ‘Purple Sensation’. Plant them 10-15cm deep and the same measurement apart from each other. The larger varieties, such as ‘Globemaster’ and Cristophii should be planted 30cm apart due to the size of their heads when flowering.
Hang your blooms for all to admire
Hanging baskets cheer up any entrance to a house and are so inviting. You can mix herbs in with annuals or perennials, do all herbs, or just plant ferns if the basket is to hang in a shady spot.
Make sure you plant all around the basket, use a good compost and add a slow-release fertiliser and water-retaining crystals. Keep deadheading for continued flowering.
See the insider style tricks you can steal from the Chelsea Flower Show
Hanging baskets cheer up any entrance to a house and are so inviting. You can mix herbs in with annuals or perennials, do all herbs, or just plant ferns if the basket is to hang in a shady spot.
Make sure you plant all around the basket, use a good compost and add a slow-release fertiliser and water-retaining crystals. Keep deadheading for continued flowering.
See the insider style tricks you can steal from the Chelsea Flower Show
Get staking
May really is the last chance you have to add supports to your perennials before the beds get too overcrowded for you to be able to get in among the growth. You can use pea sticks – the firm, young branches of birch or hazel (pictured) – to create a rustic-looking, open-weave dome for your plants to grow inside.
For fairly low-growing plants, use 1.5m pea sticks around the edge of the clump and bend them inwards and across, weaving them together at the top; your dome will end up around 40cm high. You could also use hazel wigwams or make some supports with canes and string. Wind damage to plants such as delphiniums is upsetting, so early staking is advisable.
May really is the last chance you have to add supports to your perennials before the beds get too overcrowded for you to be able to get in among the growth. You can use pea sticks – the firm, young branches of birch or hazel (pictured) – to create a rustic-looking, open-weave dome for your plants to grow inside.
For fairly low-growing plants, use 1.5m pea sticks around the edge of the clump and bend them inwards and across, weaving them together at the top; your dome will end up around 40cm high. You could also use hazel wigwams or make some supports with canes and string. Wind damage to plants such as delphiniums is upsetting, so early staking is advisable.
Add a meadow
Everyone loves a meadow – and there is nothing better for attracting bees. You don’t need masses of space, either – you can even buy mixes these days that will give you an instant annual meadow in a window box! But if you have the space and patience, the bees will benefit from as large a meadow as you can fit in.
Make sure you sow the right seeds for your soil conditions, and include yellow rattle in the mix – that will weaken grass and allow other species to flourish. You can also let the buttercups grow and add camassia bulbs (pictured), which are happy with hard soil for a lovely spring show.
Everyone loves a meadow – and there is nothing better for attracting bees. You don’t need masses of space, either – you can even buy mixes these days that will give you an instant annual meadow in a window box! But if you have the space and patience, the bees will benefit from as large a meadow as you can fit in.
Make sure you sow the right seeds for your soil conditions, and include yellow rattle in the mix – that will weaken grass and allow other species to flourish. You can also let the buttercups grow and add camassia bulbs (pictured), which are happy with hard soil for a lovely spring show.
Trim evergreen hedges now
Hedges are starting to look untidy and need a good spring hair cut. Although some people leave cutting their Buxus (box) hedges until Derby Day (6 June), you can give them a trim now if you prefer. Buxus doesn’t take to being cut back hard and it’s preferable to use hand shears to prevent bruising, which will turn the leaves brown.
When pruning evergreen hedges, aim to remove a third of the older wood in total. Thin out any overcrowded shoots and, when finished, give the hedges a good mulch and feed. You can use a general-purpose fertiliser or one with a high potassium content, or even use rose food. Remember to check for nesting birds before you cut any hedges.
Hedges are starting to look untidy and need a good spring hair cut. Although some people leave cutting their Buxus (box) hedges until Derby Day (6 June), you can give them a trim now if you prefer. Buxus doesn’t take to being cut back hard and it’s preferable to use hand shears to prevent bruising, which will turn the leaves brown.
When pruning evergreen hedges, aim to remove a third of the older wood in total. Thin out any overcrowded shoots and, when finished, give the hedges a good mulch and feed. You can use a general-purpose fertiliser or one with a high potassium content, or even use rose food. Remember to check for nesting birds before you cut any hedges.
Prune early-flowering clematis
Early blooming varieties of clematis, such as Alpina and Montana, as well as the evergreen Armandii, can now be pruned. Don’t be afraid to chop Montana, which can be very vigorous, with a pair of shears: it never fails to grow back.
With the other early bloomers that have flowered on last year’s growth, prune back the dead and winter-damaged shoots to a pair of healthy buds. Always apply a general fertiliser after pruning.
Early blooming varieties of clematis, such as Alpina and Montana, as well as the evergreen Armandii, can now be pruned. Don’t be afraid to chop Montana, which can be very vigorous, with a pair of shears: it never fails to grow back.
With the other early bloomers that have flowered on last year’s growth, prune back the dead and winter-damaged shoots to a pair of healthy buds. Always apply a general fertiliser after pruning.
Give the veg patch some love
The weeds really start to take hold in May, especially in-between your newly sprouting vegetables, so keep on top of them. Start to thin out carrots, lettuce and spinach and continue to ‘earth up’ potatoes, which means covering emerging shoots to stop any possible frost blackening them.
There’s so much that can be sown this month: French beans, runner beans, beetroot, chicory, kale, peas, radishes, spring onions, cabbage and broccoli. You may want to protect carrots from carrot fly – if so you can get some horticultural fleece.
The weeds really start to take hold in May, especially in-between your newly sprouting vegetables, so keep on top of them. Start to thin out carrots, lettuce and spinach and continue to ‘earth up’ potatoes, which means covering emerging shoots to stop any possible frost blackening them.
There’s so much that can be sown this month: French beans, runner beans, beetroot, chicory, kale, peas, radishes, spring onions, cabbage and broccoli. You may want to protect carrots from carrot fly – if so you can get some horticultural fleece.
Do the ‘Chelsea chop’
Towards the end of the month, late-flowering perennials will benefit from what is called the ‘Chelsea chop’. It may seem harsh, but you will have more compact plants that are less leggy and will flower more prolifically, even though they might be in bloom a little later.
Plants you can do this to include sedum, Echinacea Purpurea, rudbeckia and Phlox Paniculata. Other plants that benefit are asters and Campanula Lactiflora.
Cut back the plants with shears or secateurs to about one third and you will have much fuller plants with more blooms.
TELL US…
What are you doing in your garden this month? We’d love to hear your tips or see your photos in the Comments below.
Towards the end of the month, late-flowering perennials will benefit from what is called the ‘Chelsea chop’. It may seem harsh, but you will have more compact plants that are less leggy and will flower more prolifically, even though they might be in bloom a little later.
Plants you can do this to include sedum, Echinacea Purpurea, rudbeckia and Phlox Paniculata. Other plants that benefit are asters and Campanula Lactiflora.
Cut back the plants with shears or secateurs to about one third and you will have much fuller plants with more blooms.
TELL US…
What are you doing in your garden this month? We’d love to hear your tips or see your photos in the Comments below.
Dahlias add that late-summer burst of colour with big, happy, sunny blooms, and May is the ideal time to plant these tubers. There are so many varieties and they are all wonderful as cut flowers for the house. You can even grow them in large pots outdoors.
Plant them about 10-15cm deep and make sure the ‘eyes’ – the tiny pointed bits on the tubers’ necks that the dahlias will grow from – are facing upwards. The hole should be wide enough to accommodate the tuber, then cover it with soil and water well.
Most taller varieties will need staking as they grow, so make sure you do this with nice supports or canes with string. Once they start to bloom, feed with a high potash liquid fertiliser every two weeks and deadhead regularly.
Browse creative ways to display cut flowers in your home