Cherry Blossom Time (though this picture was taken at Kew Gardens on 7th May last year, I suspect the display was late by a more than a week or two on account of the freezing temperatures endured all through the month of March. This set everything back – I didn’t see a rose in bloom until July! This year, after a mild winter, I suspect we will be just a little early.
Longer days, warmer temperatures, April showers – lots to be doing in the garden this month, including-
- Continue watering newly planted trees and shrubs if the weather is dry
- Plant evergreen trees and shrubs. In cold, exposed sites, erect a windbreak to protect them.
- Spray roses against blackspot
- Trim grey-leaved shrubs to keep them bushy
- Tie in new shoots of climbers
- Prune early-flowering shrubs
- Prune shrubs grown for large or colourful foliage such as cotinus
- Divide perennials
- Stake tall-growing perennials
- Protect young growth from slugs and snails
- Pot up or transplant self-sown seedlings that you come across in beds and borders
- Keep weeding. Annual weeds can be hand-pulled but always dig perennial weeds right out.
- Deadhead daffodils
- Sow annual climbers and grasses
- Plant new aquatic plants
- Sow or turf new lawn – ditto for repairing bald patches
- Feed established lawns
- Sow greenhouse crops such as tomatoes
- Continue sowing and planting vegetables outdoors
- Prick out or pot up seedlings before they get congested and grow leggy
- Last chance to cut down any dead growth left over winter on perennials, especially grasses, before there is too much risk of damaging new shoots
- Last chance to plant summer-flowering bulbs
- Last chance to sow sweet peas.
- Get ahead and prepare trenches for runner beans
- Get ahead and plant up hanging baskets if you have space under glass to shelter them for a few more weeks.
A week by week guide from Gardeners World –
and finally, from Dan Pearson in the Guardian (March 2013)
Seeds of time
As soon as the ground reaches 6C you can start to sow salad, beetroot and annual herbs, such as dill and rocket. The same goes for hardy annuals, such as Larkspur, Nigella or the Pictorial Meadow seed mixes. If your soil still feels cold lay fleece directly over freshly sown seed to hold in the heat.
Continue to sow seed of half-hardy annuals under cover. Sow in small pots rather than trays to save space, and prick out after the first leaf is fully formed. A pinch of anything as fine as salt will be enough for most gardens, but larger seed such as Ipomoea, Tagetes and squash can be sown in pairs in 10cm pots. Never handle seedlings by the stem when pricking out. To avoid damage, gently grasp the first set of primary leaves. Over-sow bald patches in the lawn and keep off the grass for two to three months after germination.
If you are turfing, this is the perfect time to do so. Work from boards to tamp the sods gently into place and spread your weight. Stagger the joints as you would bricks in a wall. If the weather is dry you may need to water to prevent curling at the edges. Feed established lawns with a slow-release organic fertiliser high in nitrogen to get things off to a good start.
Potatoes and onions
Plant out seed potatoes once “chitted”. Grow half a dozen in a dustbin if you have room in the greenhouse for a plate of earlies. Line out then just plunge onion sets and shallots into ground that has been firmed and raked. They like soil manured the previous year. Until they have formed their first leaves and have got their roots down, net onions to prevent blackbirds pulling them free.
Bed of roses
Foliage-feed the first new growth on the roses and continue to do so every three to four weeks to avoid the use of toxic rose sprays. A tonic such as Sulphur Rose (greengardener.co.uk) will help to ward off blackspot and mildew which, with last year’s wet summer, will be lying dormant and ready to pounce. A handful of slow-release organic blood, fish and bone spread evenly about the roots will set up the health of your plants.
Pick rhubarb that has been growing away under forcers. Do not over-pick and remember to lift the forcer off as soon as you have had your fill to allow the plant its right to light, so it may replenish its resources for next year.
Under the covers
Cover blossom on wall-trained fruit if you hear of a frost warning. A layer of fleece will do the trick. The same goes for spuds once they break ground.
I prefer to stake any plants early on to let them grow into their support rather than wade into the beds when growth is up and fragile. Staking late in the day is a fractious exercise and the plants always look bundled up if you stake too late.
In an ideal world one would only grow a handful of plants that need support, but in small gardens and where plants are drawn up to reach for light, this will be necessary. Hazel twigs are excellent, but steel hoops are most easily installed.
Make wigwams for sweet peas and climbing beans. Plant sweet peas now, but beans must wait until the Chelsea week in May or later if the weather still hasn’t warmed up.
Evergreens, such as rosemary, lavender, bay, myrtle, sage and thyme, can be pruned as soon as the winter is over. Never cut into old wood and always leave enough foliage to help draw energy back into the limbs.
Beware the scarlet lily beetle (pictured above). Hunt down the adults, which will be out in first sunshine.