7:00am Saturday 7th April 2012
A look at trials of new patio plants to find out which will be worth growing this year - plus, find out what else needs doing in the garden this week.
By Hannah Stephenson.
As summer beckons, many gardeners will now be deciding which patio plants to feature in their scheme, but it's a difficult job as there's so much choice and plants can vary greatly in quality.
The perfect summer container plant should be long-flowering and disease-resistant. But many simply don't do that job.
To save you some of the bother of trial and error, Which? Gardening, the Consumers' Association magazine, has now produced a report after growing more than 35 new varieties suited to containers or baskets before they were released to the public.
The plants, which were bought as plugs or young plugs last April, were grown in good quality container compost with added slow-release fertiliser.
The planted containers were kept in polytunnels until all risk of frost had passed and then brought out in June, watered and deadheaded as required.
Among the pick of the crop were Osteospermum Serenity series (Mr Fothergill's; Unwins), with its soft pastel or terracotta-toned flowers that mature to a deeper, warmer shade, and the Nemesia Lady series, a deliciously scented variety which looked great in mixed plantings with Calibrachoa 'Can-Can Rose Star' and Pelargonium 'Caliente Pink'.
The white Nemesia 'Sweet Lady' was the longest flowering of three highly scented varieties and still looked good in September.
For those interested in new basket plants, winners included Petunia 'Sanguna Atomic Blue', which brings drama to any arrangement, with its dark throated flowers with dark veins leading to a deep-mauve colour of the rounded petals.
It carried on flowering when other plants were waning, trailed well and didn't suffer from having all the flowers at the bottom of a curtain of green growth (B&Q; The Garden Centre Group; Homebase).
For a burst of yellow in a mixed planting basket, Bidens 'Solaire Semidouble' didn't disappoint, forming a dense trailing mat of fine foliage covered with hundreds of tiny, vibrant flowers that have an extra set of petals around the eye, forming a frilly collar. The plants grew well, flowered strongly all summer and were easy deadhead. (B&Q; garden centres) Lovers of busy lizzies (Impatiens) whose plants succumbed to a widespread outbreak of downy mildew last summer may be better off growing alternatives such as the New Guinea-type hybrid impatiens or begonias, both of which will succeed in similar conditions, according to Which? Gardening.
Last year trialists grew several varieties of sunpatiens (a New Guinea hybrid), which all performed admirably and showed no signs of being affected.
The Sunpatiens Compact series were extremely vigorous, tolerant of both sun and shade and produced beautiful, vibrant flowers which required only a little tidying to stay looking pristine.
Of course, no summer planting scheme would be the same without the trusty lobelia - and Lobelia 'Super Star' lived up to its name, earning the accolade of the best lobelia in the trial.
This small-flowered, bicolour variety flowered prolifically, starting in June and continuing long after other lobelias had given up entirely.
:: The full report on new patio plants is in the April edition of Which? Gardening. To get a free copy of the Which? Your Easy Guide To Gardening, call 0800 389 8855 and quote code VEG441F Best of the bunch - Euphorbia These hardy perennials are a brilliant choice for year-round interest but it isn't the flowers that make them significant, but the eye-catching bracts which appear in late spring or early summer.
While euphorbias form a diverse group including succulents and poinsettias, it's the hardy types you want to include in your herbaceous borders, such as E. polychroma, which has a neat dome of bright yellow bracts, and E. characias, which offer architectural value and height.
Most euphorbias prefer sun but will tolerate partial shade and grow in most soils which do not become waterlogged.
E. polychroma fills the gap between spring bedding and the first of the summer perennials, combining well with purple sage or Geum rivale, while E. characias looks great with silvery foliage plants or as a stand-alone plant in a gravel bed.
For a different hue, try E. griffithii 'Dixter', whose deep orange bracts appear in April and again in August.
Be warned that all euphorbias are poisonous, except the poinsettia, and their milky sap can irritate the skin.
Good enough to eat... Sowing lettuce It's one of the easiest veg to grow and can provide you with salad leaves for virtually the whole year. Now is the time to start sowing a short row of lettuce every other week to ensure a regular supply of salad leaves throughout the summer.
Sow seeds in small pots for containers and vegetable plots, sowing a few pots of different varieties and keep the pots somewhere cool and sheltered.
If you're sowing directly into the ground, early sowings should be planted under cloches which should have been in place for a couple of weeks to help the soil warm up.
Space plants 30cm apart each way, unless you are growing small varieties such as 'Little Gem', which can be placed slightly closer together.
Water the crop regularly and you shouldn't have to do much more. Early in the year they grow best in a sunny but sheltered spot, while in summer they will tolerate light shade and may bolt in full sun.
If you're growing lettuces in a vegetable patch, grow them in a different part of the plot each year or incorporate them into a crop rotation.
Three ways to... Keep your compost healthy 1. Use a mixture of materials, including kitchen scraps (but not meat), garden debris and lawn mowings. Too much of one ingredient, especially grass clippings, can make the heap slimy.
2. Never put perennial weeds or diseased plants on to the heap, as the heat inside may not be enough to kill the bacteria or the weeds and you risk spreading them further when you come to use to compost.
3. To speed up the rotting process, layer your compost ingredients, dampening them down if dry and then top them with a bucket of garden soil or animal manure to provide bacteria to make the heap rot.
What to do this week :: Pull off the dead outer leaves of phormiums and divide overcrowded clumps.
:: Cover strawberry crops with tunnel cloches, opening the sides every day to allow pollinating insects to do their work.
:: Sow sweet peas directly into their flowering position.
:: Chit maincrop potatoes and plant sprouted tubers of early varieties.
:: Sow and plant out vegetables including beetroot, broad beans, carrots, celeriac, spinach, onions, peas and turnips.
:: Sow tomato seeds in a heated propagator or on a warm windowsill but don't plant outdoors until all danger of frost has passed.
:: Trim back the dead flower heads on winter-flowering heathers with shears, making sure you don't cut into old wood.
:: Prune hydrangea paniculata and hardy fuchsias if they look tall and untidy after the winter.
:: Transplant cabbages sown in seed beds earlier in the year to their final resting place, watering them well the day before.
:: Prepare grass for sowing or turfing.
:: Support pea plants using twiggy branches, to stop pods resting on the soil.
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