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Oak Leaf Gardening Monthly Cuttings
Newsletter 12 - May 2012
What to do now

Ornamental plants

  • Finish off sowing hardy annuals early this month. Continue to sow biennials such as honesty, foxgloves, stocks and wallflowers.
  • Take cuttings from pelargoniums, fuchsias and other tender perennials.
  • Keep on top of the pricking out, pinching out and potting on of seedlings.
  • Harden off and plant bedding and tender plants (leave towards the end of the month in cooler climates) including containers and hanging baskets.
  • Plant out summer bulbs including acidanthera, cannas, eucomis, dahlias, gladioli, galtonia, calla lilies, arisaemas, liatris, oxalis and tuberous begonias.
  • Clear spring bedding to make way for summer blooms.
  • Continue to deadhead spring flowering bulbs and camellias. Cut down the foliage from spring flowered bulbs six weeks after the flowers have died down.
  • Divide congested clumps of daffodils.
  • Put supports in place for tall perennials.
  • Feed acid loving plants, such as camellias, with an ericaceous plant fertiliser.
  • Train climbers such as clematis while the shoots are still young and pliable.
  • Prune spring flowering shrubs such as Ribes sanguineum, Clematis armandii, pyracantha, chaenomeles and forsythia after flowering.
  • Clip beech, hornbeam, box, thuja, privet, Lonicera nitida and leyland cypress hedges late this month, making sure no birds are nesting in them.
  • Prune alyssum, arabis and aubrieta after flowering.
  • Pinch or prune out any reverted (green) growth on variegated plants.
  • Divide overgrown waterlilies.
Fruit and veg
  • Sow tomatoes under glass and, later in the month, sweet peppers, chillies, aubergines, melons and cucumbers.
  • Outdoors you can sow swedes, beetroot, maincrop carrots, Brussels sprouts, autumn cabbages, autumn/winter cauliflowers, calabrese broccoli, peas, Swiss chard, radishes, lettuce, mangetout, French beans, runner beans, turnips, endives, fennel, kale, kohl rabi, sweetcorn, courgettes, squashes (including butternut squash), pumpkins and spring onions.
  • Sow chicory for forcing in the winter.
  • Continue to earth up potatoes regularly.
  • Put codling moth traps up in apple trees.
  • Keep soft fruit bushes well watered.
  • Check gooseberry bushes for pests, particularly sawfly larvae on the leaves.
  • Thin out new shoots on raspberries so they’re about 10 to 15cm apart.
  • Put straw or other liners under strawberries to protect the fruit from grey mould.
  • Pot up some strawberries and grow them in the greenhouse for an early crop – but make sure you keep the door open for a period each day to allow fertilising insects to get to them.
  • Cover or put up a barrier (of fine mesh/plastic film) 45cm high around carrots to protect them from carrot fly. Cover cabbages with a similar material to keep off the cabbage white butterflies.
  • Start harvesting your asparagus, lettuce, radishes, rocket, baby potatoes and overwintered onions.
General tasks
  • Mow your lawn weekly to around 2.5cm, longer if a drought is forecast. This is your last chance to re-seed any dead patches before the summer.
  • Use a 'weed and feed' product on your lawn, if you didn't do it last month.
  • Keep on top of the weeding.
  • If you get a couple of dry days, hoe over the soil surface to bring weed seedlings to the surface where they will wither.
  • Apply summer shading to your greenhouse towards the end of the month to protect plants from scorching.
  • Ventilate greenhouses during warm days, but remember to close them up in the evening.
  • Install water butts on all downpipes; they’re invaluable in droughts.
  • Scoop duckweed and blanketweed out of ponds and re-stock with aquatic plants.
Tulipa 'Spring Green'Plant of the month

Tulipa ‘Spring Green’ is one of the more subtly coloured tulips, whose delicate beauty is best appreciated when viewed from above. It makes a particular impact when mass planted in beds, borders or containers. Find out more...

Problem of the monthAphids

Aphids are sap-sucking insects which are prevalent on many plants over the warmer months. They come in a multitude of different colours and may be winged or wingless.

Plants will become distorted and weakened by the aphids' feeding. You may notice 'sooty mould' growing on plants, which is attracted by the sticky honeydew excreted by aphids. Aphids may also transfer diseases between plants.

Find out more about aphids and how to deal with them...

In the news

Bird feeders prove good for pest control as well as for birds

Research by the University of Reading has shown that gardens with bird feeders have fewer colonies of greenfly and any colonies which do establish are eradicated more quickly. Meanwhile, ornithologist Bill Oddie has encouraged gardeners to continue feeding birds throughout the summer as parents strive to find enough food for themselves and their chicks.

Things to do before you're 11¾

The National Trust has launched a campaign to encourage children into the great outdoors by releasing an enticing list of 50 things every child should do before they're 11¾. The list, which includes activities like climbing a tree, making a mud pie and playing a grass trumpet, is part of an interactive website which encourages children to tick of their completed adventures and earn 'explorer' points.

The peat debate continues

The ongoing research by the DEFRA taskforce on peat usage is struggling to make progress, with peat experts stating that the taskforce have failed to identify and quantify the key issues with peat usage, which are required to create the 'road map' to an acceptable usage level, which is due in June. For gardeners, however, initiatives to reduce peat usage continue: Following criticism by the taskforce of their peat based topsoil 'Verve' earlier this year (39% peat), B&Q are due to introduce a new peat-free topsoil product this summer.

Be happy - live near a tree!

Recent research by the Forestry Commission has shown that people living near trees feel more relaxed and can think more clearly. The research focussed on 200 tenants of a housing charity, half of which lived in areas of high tree cover, the other half having few trees nearby. The outcome showed that those living near trees had higher happiness scores (when other factors were broadly the same).

Phytopthora outbreaks increase

Outbreaks of the fungal disease Phytophthora, which can have a devastating impact on trees, have been identified in Cornwall, Devon and Scotland this spring, affecting rhododendrons and junipers. The infected plants have been destroyed. DEFRA continues to monitor outbreaks with the aim to control and, if possible, eradicate this disease from the UK.

No Joe for BBC Chelsea coverage

This year's BBC TV coverage of the Chelsea Flower Show will be lacking the cheery face of Joe Swift. Joe will be designing a garden for retailer Homebase at the world famous event and this sponsorship deal conflicts with his BBC contractual obligations. However, rest assured that the rest of the presenting team will be there, including Alan Titchmarsh, Nicki Chapman, Carol Klein, Rachel de Thame, James Alexander-Sinclair and Christine Walkden.


Our garden show survival guide

Ticket for the RHS Chelsea Flower Show 2012As the spring blooms are starting to die back they are being replaced by garden shows popping up everywhere! Yes, we're well into the season for these wonderful displays of horticulture which inspire us to try out new plants, admire extravagant designs, and spend a small fortune on gardening gadgets that we really don't need.

So, with the RHS Chelsea Flower Show only a few weeks away, and other delights such as Gardening Scotland, BBC Gardeners' World Live, RHS Tatton Park and numerous local shows on the horizon, we thought we'd share our top tips for surviving, and enjoying, garden shows:

  • Plan ahead to make sure you don't miss anything and don't end up walking further than necessary.
  • Take a folding box trolley if you have a picnic to carry around or intend to do a lot of shopping.
  • Take waterproof clothing in case of rain - umbrellas are a real no-no.
  • Stuff a couple of plastic bags in your pockets to put on rain soaked seats/benches.
  • Wear comfortable footwear which (if rain is forecast) you don't mind getting a bit muddy.
  • Take your own lunch - buying food at shows can be a bit pricey.
  • Take cash/cheques if you want to shop as some stalls won't accept credit cards.
  • Go on the last day to grab bargain plants in the end of show sell-offs.
  • Accept bags of promotional literature, they often contain free seeds too.
  • Chat to the exhibitors; share their enthusiasm and get tips from the experts.

Read our full blog on surviving garden shows for more tips...


What's on this month

Hopefully the April showers will bring out plenty of May flowers for the many gardening events happening this month, some of which are:

  • 5th May - Plant Swap & Growing Workshops, Barracks Lane Community Garden, Oxford.
  • 5th to 7th May - Milton Keynes Garden & Home Show, Milton Keynes, Buckinghamshire.
  • 10th to 13th May - Three Counties Spring Gardening Show, Malvern, Worcestershire.
  • 11th to 13th May - Lotherton Hall Garden Festival, Aberford, Leeds, West Yorkshire.
  • 11th to 13th May - Norfolk Spring Garden Show, Costessey, Norwich, Norfolk.
  • 12th May - Green Fingered Fete & Plant Sale, The Eden Project, Cornwall.
  • 13th May - NGS Open Garden, Abbey Road, Fareham, Hampshire.
  • 13th, 20th & 27th May - NGS Open Garden, Cwm-Weeg, Newton, Powys.
  • 18th to 20th May - Essex Garden Show, Brentwood, Essex.
  • 18th to 20th May - Fife Diamond Garden Festival, various locations, Fife.
  • 19th to 20th May - Northhants Spring Home & Garden Show, Earls Barton, Northampton.
  • 22nd to 26th May - RHS Chelsea Flower Show, Chelsea, London.
  • 25th to 27th May - Cambridgeshire Garden Show, Godmanchester, Cambridgeshire.
  • 27th May - Iris Day, Godinton House & Gardens, Ashford, Kent.