There has never been a better time to try delphiniums and if you sow them now, grow them on in pots and overwinter them in a cold frame or sheltered spot you’ll have sturdy, young plants that will quickly grow away to flower in summer. They great thing is that there are delphinium varieties to fit in all kinds of spaces, from the smaller, open-flowered Belladonna types to the stouter tightly-bloomed spires of the Centurion series and the traditional Pacific hybrids. Modern breeding has improved the stature of the plant, with stronger more compact stems being better able to stand on their own without staking, producing stronger, cleaner colours in a range of petal formations from single to completely double, with prominent ‘bees’ in the centre adding to the allure. If the main spike is removed once the blooms are over side shoots will form to continue the display.
The Belladonna types are useful for more informal cottage gardens, ideal for massing among other perennials and annuals or even pots. The Delphina types have greater stature, but are very compact, ideal for smaller borders, while taller varieties are more effective if given space to develop in herbaceous or mixed borders. Taller varieties do better in moist, but well-drained rich soil with plenty of organic matter to generate strong, vigorous growth to get the stature they need. All thrive in sun or semi-shade, but need more moisture the hotter it is. They struggle on dry, impoverished soil, producing weak growth and a disappointing display of bloom. Feed them with a general-purpose fertiliser and liquid feed with a high potash fertiliser when the flower spikes form and give them a water and keep them mulched if the weather turns dry. The main scourge of delphinium is of course slugs and snails which love to devour fresh young growths in spring, so try your best to get them through this period so they grow away from danger and you’re all set for a display to remember!
Best laid plans never quite work out and that’s especially true in gardening, when there are so many factors that can influence the way our plants perform and knit together. The fact remains we all have gaps, whether we grow our plants in borders or pots, but thankfully there are a palette of plants we can use to come to the rescue.
Assess your predicament, taking note of the style of plant best suited to the space, whether narrowly upright or spreading, and whether one or more plants is required. Assess whether you need something permanent or just a temporary filler for the summer as this will also influence your decision. Before plumping for something expensive take a look around your garden centre or nursery for a few bargains, as there are many on offer at this time of year.
Crocosmia add a vertical accent and a splash of vibrant colour, while slender gaura is far more subtle in shades of pink and white, whose whippy branches can be threaded through surrounding plants. Dahlias of all kinds are a must, particularly the single-flowered kinds with purple foliage which will continue flowering till autumn. Shrubby salvia are a godsend, particularly the S. jamensis types, which includes the bicoloured ‘Lips’ series, which are durable, surviving in coastal gardens and hot sun and are good whether filling gaps in borders or in containers.
In establishing your new plant give it space to grow by snipping back encroaching plants and loosening and preparing hard ground first. Even rescue plants can’t work miracles!
It’s no surprise that gardeners often name the rose as their favourite flower. Roses bloom profusely all summer and into autumn; many are deliciously fragrant and plants are tough as old boots, tolerating the worst that the British weather can throw at our gardens.
Roses are often associated with English stately homes and traditional cottage-style borders, but choose the right variety and it’ll put on a stunning display in a container – perfect if you only have a small garden, patio or balcony.
For best results, choose patio or miniature roses, which thrive in pots with a depth of 25-38cm (10-15in). If you’re keen to grow a climbing or ground cover rose in a pot, a large container is a must, with a depth of 35-45cm (14-18in).
Where traditional floribunda or English roses are to be grown in pots, choose extra-large containers with a diameter and depth of around 50cm (20in). Roses have long roots – that’s how these deep-rooted plants anchor themselves in border soil and tap nutrients from the depths – and lengthy roots won’t thank you for being crushed into a shallow pot.
For maximum impact, consider positioning several pots together by a sunny doorway, containing roses with contrasting colours of scented blooms. Water daily in hot weather, dead-head regularly and feed every spring with a granular rose fertiliser. Top-dress every two years by scraping away the top couple of inches of compost and replacing it.
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Sow Zinnias for a summer sizzle
Zinnia are sure-footed performers, guaranteed to deliver long-lasting, high-season colour, especially in hot, dry weather. They’re easy to grow from seed sown now until the end of April under glass or on a sunny windowsill to flower from mid-summer, or sown outdoors in warm soil up from mid-May for late-season blooms.
Zinnia is a group of vibrantly coloured annual plants in the daisy family Asteraceae from southern South America, Mexico and central South America, from small foot-tall bushy plants, to taller more statuesque species up to 3ft or more tall. Bred in both single and double forms they come in a range of astonishing colours except blue, often bi or multi-coloured. Flowers can be single or double forms, with single flowers providing an important source of nectar for butterflies.
Zinnias are ideal for summer bedding in borders, subtropical planting schemes and patio pots. Taller varieties also make excellent cut flowers. Removing spent flowers of larger varieties will encourage more to form. They need a sunny, sheltered position, in any moist, but well-drained soil, but don’t need lashings of fertiliser, performing readily in soils of average or even poor fertility. Being tender, harden off plants before planting out from mid-May after the risk of frost has passed when they will quickly grow away to give their all till summer ends.
New varieties to try
RHS Award-winning varieties that are bursting with summer colour
The vibrant pops of colour crocosmia brings to the summer scene makes them one of the most useful perennials to grow, at home in a country-style border or vibrant subtropical plantings with bananas, cannas and dahlias. By using varieties flowering at slightly different times you can plant a succession for blooms from July through to September.
Crocosmia are bulbous perennials growing from small brown corms, which generate chains of new corms and sometimes also short rhizomes to create clumps of upright, often decoratively pleated sword-like foliage, anywhere between 60cm- 1.2m (24-48in) tall.
It’s the arching sprays of tubular flared flowers we adore which are held on tough, wiry stems, among or above the foliage, which makes them effective, eye-catching gap fillers between other perennials or shrubs. Flowers come in shades of vibrant red, clear yellow, rich orange to salmon tones, with all shades and bicolours in between.
Varieties such as ‘Dusky Maiden’ also have dark, bronzy foliage adding to their appeal.
Originating in damp South African grasslands these bulbous perennials love moist, but well-drained soil and full sun. They establish more effectively from pot-grown specimens than dry bulbs bought in bags, but are easy rejuvenated and propagated by lifting and dividing established clumps every three to four years just before they shoot in spring.
New varieties to try
Hardy annuals are one of the most dramatic, easiest and cost-effective splashes of colour you can create in a garden, all for the price of a packet of seeds. You don’t even need a greenhouse to get them going, just a small patch of finely raked soil. Now’s the time to choose what you want to grow, and there’s so much on offer.
Annuals are versatile, having many other uses. Cornflowers and marigolds have edible flower petals, and are good for cutting or drying. If you have pollinators in mind select single rather than double flowers where possible, and look for varieties particularly recommended as good food plants, providing nectar or pollen. Plan your display balancing the heights, spreads and colours of the various varieties. You can either sow in patches for smaller types, or in lines for those which grow taller, saving seed. Avoid sowing in gaps soon to be swamped with neighbouring perennials.
All annuals need is light and moisture and nature does the rest. Rake the soil so it’s free of lumps. You can either sow directly onto the soil, or you can sow onto a 12-25mm (½ to 1in) layer of washed horticultural sand or sterilised seed compost, which will create a weed-free seed bed, allowing seedlings to establish without competition from feral seedlings. This technique also allows you to sow more thinly as more plants will establish. Keep seedlings watered, thinning them out as they start to grow and provide twiggy supports for weaker growing types. Feeding or over rich soil will also cause plants to over-grow, with weak stems likely to collapse. Sowing at two-week intervals will also prolong the display.
How to sow for superb results
In terms of ornamental plants, and summer-flowering bulbs in particular, South Africa has given so much to British gardens. The freesia, Ixia and sparaxis all come from small corms, while the tulbaghia, an onion relative, is usually bought as a potted plant, than dry bulbs.
All are easily grown, producing a vibrant multicoloured range of blooms on wiry stems, anything from 6in to 18in tall. They are ideal for the front of a sunny border or pots. Plant the small corms about 5cm (2in) deep in a sunny, sheltered spot in well-drained soil and water in or if in pots use John Innes No 2 compost.
Taller types benefit from a few twiggy supports pushed in among stems. Keep watered until flowers fade, then allow to dry off for the summer. In colder gardens lift them like gladiolus in late summer, or replant fresh corms next year. A mulch in winter will provide some protection.
Tulbagia violacea is different, growing from rhizomes, producing a clump of strappy, garlic-scented leaves. Loose heads of sweetly aromatic flowers appear in summer continuing into autumn. Both leaves and flowers are edible. Again, it likes well-drained gritty soil in sun and the hardiest of its clan it will survive winter if mulched, or keep in pots and bring indoors.
Sow these summer lovelies now!
There is nothing more exciting than the anticipation in sowing seeds of half-hardy annuals and perennials that will result in a show of colour and drama in the summer garden. Seeds of such varieties need to be sown from now into April to ensure you have big enough plantlets to bed out in May, so they make sizeable plants before bursting into bloom from June onwards.
There’s so many types to choose from, they’re easy to get going so if you have a little greenhouse space or a sunny windowsill growing from seed is cheaper than purchasing plugs, and you’ll also have the choice of more varieties, particularly if you have a colour scheme in mind.
Most summer bedding plants love sun, but need moist, well-drained soil with plenty of feeding to keep plants growing strongly. Removing spent blooms or flower heads will also encourage more flowers to form. If you need height try tobacco plants, such as newly launched ‘Starlight Dancer’ with loose heads of dangly flowers, while salvia ‘Lighthouse Purple’ would look good associated with petunia Limoncello along border edges or in containers. The shifting colours of French marigold ‘Fireball’ are a feature in themselves and guaranteed to spark comment from admirers.
Let begonias bring a fiesta to summer
The promise of spectacular blooms from vibrant-toned begonias should be enough to spur any gardener into action and now’s the time to start, especially if raising varieties from tubers.
Many others are easily raised from plug plants usually mailed out from mid- spring from on-line retailers, but you need to order favourite varieties now before they sell out. Begonias are generally trouble free and once established will thrive in sun or semi-shade with a succession of blossoms from June to September and sometimes beyond.
Start tuberous varieties in a seed tray using equal parts general purpose compost and sharp sand for drainage, planting each with the depression containing the growth point uppermost, covering with 6mm (1/4in) of compost and 50mm (2in) apart. Maintain a temperature of 10-18C (55-65F), keeping the compost moist, but not wet. Once tubers produce a ball of fine roots transfer to pots 50mm (2in) larger than the root ball and grow on maintaining a temperature of 13-18C (55-65F). Pot up plug plants when they arrive into 21/3-3in pots, transferring to large containers as they develop. Harden off all plants before planting them outside after danger of frost is over. Keep plants moist and feed with a high potash liquid feed and pick off spent blossoms to encourage more flowers to form.
How to grow your begonias
These toms will beat dreaded blight!
Nothing beats a home-grown, sun-ripened tomato, so to pick those luscious red fruit as early start sowing seed under glass now to April.
While there’s a wealth of tomato varieties available there are far fewer resistant to blight disease, the scourge of gardeners trying to grow tomatoes outdoors. Recent years has seen a few F1 resistant varieties introduced, with two new ones launched this year, ‘Summerlast’, a dwarf patio variety, and ‘Crimson Blush’, a beefsteak variety. You can grow these varieties indoors too, although glasshouses offer protection from blight spores landing on foliage.
While early blight in June can be problematic, late blight in July and August quickly shrivels leaves and damages fruit. Spread by wind currents, blight spores can be carried on hands and equipment, so hygiene is key and growing resistant varieties boosts success.
Sow seeds either in modules, 2 per unit or in a 7cm (21/2in) pot in a general-purpose compost. Sow expensive varieties singly. Cover seeds, water in and germinate at a temperature of 21C (70F) lowering to a growing temperature of 18C (65F).
Prick out seedlings individually into (7.5cm) 3in pots, transferring into a 13.5cm (5in) pot as they develop. Transfer to growing bags or 30cm (12in) pots if growing indoors, or harden off before planting outdoors in late May.
Here’s some varieties to try! Click the images to find out more…
Alpine clematis will add early zing
No other climber offers such an enchanting display of delicate spring blooms in the face of unpredictable weather as the alpine clematis.
The thin stems and delicate fresh green foliage of Clematis alpina bely its hardy, durable temperament that enables it to perform to perfection whether braving flurries of snow, gusts of wind in sun or semi-shade.
Compact in habit, rarely getting over 2.5m (8ft) tall, it’s ideal for growing on fences, against walls, even those north or east facing, draped over evergreen shrubs or tree stumps or growing in pots and containers. The single or double unscented flowers are long lasting, and when spent turn into a silvery mop of feathery seeds which last into autumn, often after the deciduous foliage has fallen.
Unlike most others these clematis don’t need pruning, save thinning or shortening unwanted shots after they have flowered. Grow them in most moist, well-drained soils, to which garden compost or organic matter has been added. When growing in pots use a loam-based compost, such as John Innes No 2, feeding with a balanced slow-release fertiliser during spring and summer. They will need support such as an obelisk or tepee of twigs or branches. Planted now they will flower in the first year, but once established they are long lived giving pleasure at a critical time for many years to come.