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Oak Leaf Gardening Monthly Cuttings
Newsletter 47 - April 2015
What to do now

Ornamental plants

  • Give your beds and borders a feed, particularly around roses, spring bulbs and young shrubs/trees. Remember that acid-loving plants will need an ericaceous feed.
  • Plant new perennials and finish off dividing summer flowering ones (eg delphiniums).
  • Carry on sowing hardy annuals outside and planting out ones sown in the autumn.
  • Think about how you’re going to support taller herbaceous perennials and start to put the supports in place as the new growth comes through.
  • Deadhead your spring bulbs regularly. Cut back the foliage six weeks after the flowers have died down.
  • Climbers and wall-trained shrubs will be starting to shoot, so keep on top of tying them into their supports. Climbing rose stems should be tied in horizontally to get the best display.
  • Prune winter flowering jasmines, hydrangeas, forsythias and flowering currants.
  • Start to get rid of your winter bedding to make space for next month’s plantings.
  • Now’s a good time to plant or move evergreen shrubs and trees (including planting new evergreen hedges).
  • Plant out, or harden off, pots of dahlias, gladioli, calla lilies, arisaemas and tuberous begonias towards the end of the month when the risk of frost has passed.
Fruit and veg
  • Outside it’s time to sow broad beans, summer cabbages, Brussels sprouts, early peas, calabrese, cauliflowers, sprouting broccoli, mizuna, leeks, beetroot, radishes, spring onions, sugar snap peas, mangetout, lettuces, rocket, turnips, kohlrabi, spinach, parsnips, Swiss chard, chicory, endives, carrots, onions and hardy herbs including parsley, chervil, fennel, dill and marjoram.
  • Plant first early, second early and maincrop potatoes this month. Make sure the new shoots are covered with earth to protect them from frost.
  • Onion sets, shallot sets, asparagus crowns and globe/Jerusalem artichokes can also be planted this month.
  • Harvest the first overwintered spring onions and the last of the sprouting broccoli and Swiss chard.
  • Keep weeding your veg patch so seedlings aren’t overwhelmed by weeds.
  • Plant strawberries, figs and grapevines.
  • In the greenhouse you can sow tomatoes, melons, cucumbers, sweetcorn, basil, coriander, aubergines, peppers, okra, squashes and courgettes.
General tasks
  • Mow your lawn fortnightly, or weekly if the weather is mild and it’s growing quicker than normal.
  • Give your lawn a feed, though you may want to leave it until early May if you live in colder regions. You can also re-seed any dead patches in the lawn.
  • It’s the start of the weeding season; removing weeds from borders now will stop them self seeding and causing a bigger problem later in the year.
  • If you have slug/snail defences get them in place early this month!
  • Purchase and pot up plug plants for summer ornamentals and vegetables.
  • Ventilate your greenhouse on warm days in the morning, but shut them up again by mid-afternoon to build up a bit of heat for overnight.
  • Make sure you keep up with thinning out, pricking out, potting up and potting on your seedlings.
  • Towards the end of April, unless the weather is unseasonably cold, you can start to harden off tender ornamental plants and greenhouse-raised vegetables.
  • Take advantage of warm days to stain woodwork in the garden, particularly where it will be covered with plants later in the year.
Plant of the monthTulipa 'Olympic Flame'

Tulipa 'Olympic Flame' is in bloom this month with bright yellow flowers which have striking red 'flames' adorning the tepals. It grows to around 50cm tall and prefers well-drained soil in a sunny spot. Find out more...

Problem of the month

Crown gall (Rhizobium radiobacter) is a bacterial infection which causes knobbly 'gall' growths to appear on the stems and roots of a wide range of woody and herbaceous plants. On the whole the main problem with crown gall is the loss of ornamental value, however it can also cause reduced growth on fruit trees. Find out more...

In the news

Riverside garden opens at Bodnant

The National Trust have opened a new, 4 hectare riverside garden at their Bodnant property in North Wales. "The Far End" garden took 5 years to create and is part of the ongoing work to fully open the 32 hectare gardens for the first time in 140 years. The new garden features waterside walks, a skating pond, a boathouse and an arboretum.

Writtle College wins at Ideal Home Show

Essex-based Writtle College has beaten 5 other horticultural colleges to win the 'Best in Show' accolade at the Ideal Home Show's 'Young Gardeners of the Year' competition.

Their sustainable garden, on a 5.5m x 4m plot, includes a water feature, rain harvester, irrigation cycle, millboard walls planted with 'mind your own business' and five large alder trees which bring a woodland feel to the urban garden. All the competing gardens can be seen at the Ideal Home Show at Olympia, London, until the 6th April.

Westonbirt to fell giant redwood

Sequoiadendron giganteumWestonbirt Arboretum in Gloucestershire has announced that it will reluctantly have to fell a giant redwood (Sequoiadendron giganteum, an example of which is shown here) that has stood on its Main Drive since the mid 1800s.

Scanning with the Treetonic system has revealed a central column of decay, which is also reflected by external symptoms.

The arboretum lost another large specimen tree nearby in the winter storms. The nootka cypress (Xantheocyparis nootkatensis) had already been marked for removal.

RHS Hampton Court Show wins tourism award

The RHS Hampton Court Palace Flower Show has been recognised as the 'Garden Event of the Year 2015' by the International Garden Tourism Network. The president of this tourism body said "In the field of garden tourism events, this award and recognition is long overdue.".

The award, which is granted by a jury of garden and tourism representatives from around the world, comes in a year when the Flower Show celebrates its 25th anniversary. This year's show will run from the 30th June to the 5th July.


Plants for low-maintenance containers

Using containers can be a great way to bring splashes of colour to your garden and are particularly useful to liven up areas of hard landscaping such a patios. But remember that they aren’t completely maintenance-free –  in the summer they can need watering up to twice a day. The plants will also need feeding and the compost should be refreshed each year.

Container growing can be made easier by sticking to a few simple guidelines:

  • Have fewer, larger containers rather than lots of little ones.
  • Group containers together so they retain humidity to reduce water loss.
  • Use plastic, resin or stone containers rather than terracotta ones, as they will retain water better.
  • Mulch the top of the soil to reduce water evaporation.
  • Make sure the drainage holes at the base of the containers don’t get clogged up with compost by placing stones or crocks in the base of the pot.
  • If you have a lot of containers then invest in an automated watering system to help you out over the summer.

Then you can choose the best, low maintenance plants to use! Here are some suggestions of plants which grow well in containers and require little looking after. Many of them also provide good, evergreen structure for a container which can then be livened up by underplanting with bulbs or adding annual bedding, if you fancy doing a little more work.

  • Aucuba japonica works well in pots, although it will eventually outgrow all but the largest containers. Try the A.j. ‘Variegata’ cultivar for a speckled yellow effect.
  • Bergenia varieties are evergreen with rich hues in winter months, try Bergenia ‘Bressingham White’ or Bergenia cordifolia ‘Purpurea’ for a larger plant.
  • Carex oshimensis ‘Evergold’ is one of many Carex grasses which will thrive in containers. This cultivar has bright yellow stripes.
  • Euonymus fortunei ‘Emerald and Gold’ or E. Fortunei ‘Emerald Gaiety’ are great, evergreen rufty tufty plants which will bring a bit of brightness to a difficult spot.
  • Fatsia japonica is a magnificent architectural foliage plant which is happiest in a sheltered, shady spot.
  • Helichrysum italicum, the curry plant, has a fragrance that lives up to its name, but will keep flowering throughout the summer.
  • Houttuynia cordata ‘Chameleon’ has an eye-catching combination of green, cream and red colouring and works well in pots. Try it with Imperata cylindrica ‘Rubra’ (Japanese blood grass) to bring out the red tones.
  • Japanese hollies, which can be clipped as topiary, such as Ilex crenata ‘Golden Gem’.
  • Dwarf conifers such as Pinus mugo ‘Humpy’ give great year-round value.

Fatsia japnoica and Euonymus fortunei 'Emerald and Gold'

The tropical-looking foliage of Fatsia japonica and gold-edged leaves of Euonymus fortunei 'Emerald and Gold'.

Find out more about growing plants in containers.


What's on this month

It's all go in the garden this month, but if you can manage to drag yourself away, there's also a wealth of garden events to visit:

  • 4th to 6th April - Suffolk Garden Show, Suffolk Showground, Ipswich, Suffolk.
  • 11th & 12th April - Charity Garden Opening, Tregothnan, Tresillion, Truro, Cornwall.
  • 16th April - 'Wild Garden Weekends' Talk, Garden Museum, London.
  • 17th April - National Open Gardens Day, free entry at RHS Gardens Harlow Carr, Hyde Hall, Rosemoor and Wisley.
  • 17th & 18th April - Gardens Illustrated Festival, Malmesbury, Wiltshire.
  • 17th to 19th April - Loseley Spring Garden Show, Loseley Park, Guildford, Surrey.
  • 17th to 19th April - RHS Flower Show Cardiff, Cardiff Castle, Cardiff.
  • 23rd April - 'Scent In The Garden' Talk, Borde Hill Garden, Haywards Heath, West Sussex.
  • 23rd April - Guided Garden Tour, Pentillie Castle and Estate, Saltash, Cornwall.
  • 23rd to 26th April - Harrogate Spring Flower Show, Great Yorkshire Showground, Harrogate, North Yorkshire.
  • 26th April - RHS London Alpine Garden Show, RHS Lindley Hall, London.
  • 29th April - Red Cross Great Spring Gardening Event, Whitfield Estate, Wormbridge, Herefordshire.