Many of the best plants for late season colour come from Central and Southern America and they tend to flower more prolifically as the days shorten because in the wild they get evenly balanced days and nights. There are some fine annuals and some good perennials.
However some of the perennials (such as penstemons, hardier salvias and guara) are cut back in spring after they start to shoot at the base: they are not hardy enough to stand an autumn cut.
As a result penstemons, guara and hardier salvias can look ragged during winter. These plants also tend to lose vigour as they age, so it’s a good idea to take cuttings of penstemons and hardier salvias and to raise new gaura plants from seed. Those on wet, sticky soil may struggles to keep their plants in wet, cold winters. Plants overwinter best if planted in June as they have plenty of time to establish roots in warm soil. They all telerate dry conditions well, once their roots are down.
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This perennial comes from Louisiana and Texas and the usual form bears willowy wands of starry blush-white flowers that continue into November. It is often the last perennial in flower, so highly useful in gardens. It will overwinter in reasonable winters, but mature plants tend to become woody and brittle, so older plants should be replaced after three years. It is easily raised from seed.
Seeds can be sown in March on the surface of seed sowing compost in seed trays. Germination takes 21 days in warm temperatures of roughly 70F/20C, so a propagator or a warm windowsill is useful in cool springs. Prick out into small three-inch pots in June and then plant out in a warm, sunny position, for gauras are prairie plants that enjoy full sun and poor soil.
Gauras can be found in garden centres from July onwards.
There are pink gauras which tend to be more compact and Hardy Cottage Garden Plants (www.hardys-plants.co.uk) have a good range. They include one pink-edged white named after Rosy Hardy - ‘Rosyjane’. Other pinks include ‘Chiffon’ and ‘Ruby Ruby’. Generally most pink gauras are more compact and less elegant, but they make good patio plants.
The easiest to overwinter usually have S. microphylla in their genes, or the natural hybrid S. x jamensis. These thrive in good drainage in full sun and overwinter well. They are woody and shoot from the base, or further up, producing lipped, bee-friendly flowers mainly in pink and red. Dysons Salvias, based at the Kent garden Great Comp, are excellent and this is an inspiring garden to visit for late colour.
Here are seven good forms that flower from July to November and generally overwinter.
Long inflorescences of bright, coral-red flowers. Dies back completely in winter.
Salvia ‘Dyson’s Crimson’
An excellent plant with dark crimson-red flower on a shrubby plant, but compact and early flowering, especially after a warm spring.
Salvia ‘Icing Sugar’
Lovely pink and purple bicilour, with paler lips.
Salvia x jamensis ‘Peter Vidgeon’
The best pale-pink with shades of lilac set against grey-green foliage. Less brittle and billowing than ‘Stormy Seas’.
Salvia microphylla ‘Cerro Potosi’
A show-stopping magenta-pink slavia with great presence. It always stands out amongst the others. As William Dyson says - if you only have room for one salvia, then grow this one.
Salvia microphylla ‘Wild Watermelon’
Lovely, with wide bright-pink flowers held in dark calices. Collected in Mexico from the same mountain as ‘Cerro Potosi’.
Salvia ‘Silas Dyson’
Purple buds open to rich-crimson flowers that keep on coming.
Taking cuttings is an easy affair. Fill small seed trays with coarse horticultural sand (not fine sand as this dries out too quickly). Look for side shoots without flowers and either pull off with a heel by tearing very gently from the main stem, or snip below a leaf joint.
Ideally your cutting should be semi-ripe, that’s pliable (bendable) but not soft. if cutting material is difficult to find, you can use flowering shoots - just snip off the buds.
Remove the lower leaves and plunge into the sand so that at least half of the cutting is submerged. Keep the tray moist and out of full sun and within weeks your cuttings should have rooted. Either pot up in August, or leave your cuttings in situ until spring, but in a frost-free place. Always take your cuttings before August: they root better while it’s warm.
Seven excellent penstemons
When considering late-flowering penstemons the pinks, red and purples are better for late flower than the blues - as the laterr often P. heterophyllus blood - an earlier flowering species. Good penstemons included heritage varieties and newer ones with the Pensham prefix. Of these I prefer the smaller-flowered tubular forms for the border, but the Pensham’s Ice Cream series have large, often white-throated flowers. Hayloft Plants have an excellent range (www.hayloft-plants.co.uk).
Remember! Only cut back in spring (once shooting from the base) and always take cuttings - use the same technique as for the salvia cuttings.
‘Andenken an Friedrich Hahn’ AGM ( often sold as ‘Garnet)
Bred in Switzerland, but introduced in the 1930s by Alan Bloom who called it ‘Garnet’ - a simpler name. Wine-red refined spires of of flower produced continually between July and November. Still unbeatable.
‘Hidcote Pink’ AGM
A lovely airy pink with smaller flowers, but again very refined and floriferous.
‘Stapleford Gem’ AGM
A large penstemon with smoky flowerrs that hover between pink and blue.
‘Pensham Plum Jerkum’
Dark flowers, the same colour as plums and damsons, with small flower spikes.
Bred in the 1960s by Ron Sidwell and part of his bird series that includes the pink and white ‘Osprey’ and the very dark ‘Blackbird, this purple-black penstemon is still excellent.
Named after the late Edward Wilson, the breeder of the Pensham strain, this a wonderful, new purple penstemon and a worthy tribute.
‘Alice Hindley’ AGM
This pale-mauve penstemon has great presence. Each flower has a white throat.
Three annuals to grow from seed
Sow in March in warmth. Prick out into individual three-inch pots and plant out in June. Harden your plants off - leave them outside, some rugged, for a week - to make them less attractive to slugs.
The easiest of the three with feathery-leaves and pink or white daisies. These form large branching plants that go on and on. Deadhead until early September and then allow to set seed. harvest the prickly hard seeds on a fine day at noon and store somewhere cool. Seed companies sell lots.
Nicotiana or Tobacco Plant
Nicotianas are having a bad time as many highly bred ones are prone to a virus. Go for a healthy species instead, such as Nicotiana suaveolens. This bears fragrant white flowers held on slender pink trumpets that seem to make the flower tremble. It reaches roughly two feet in height (60 cm) and makes an excellent patio plant, being highly scented in the evenings.
Rudbeckia hirta - the Gloriosa Daisies
Mainly yellow flowers and my top selection is Sutton’s ‘Indian Summer’, a substantial AGM winning Gloriosa daisy bearing four-inch wide, plate-like yellow flowers.
Storing and starting dahlias off
- Using a general-purpose compost, part-fill large pots or deep trays. Place each tuber, add labels, cover with compost and water well.
- Take cuttings from the tubers when shoots are 3in (7.5cm) long. There are two advantages to this: plants raised from cuttings are more vigorous (exhibitors always use them) and you can raise perhaps four plants from each tuber and still plant the tuber.
- Fill small pots with John Innes No 1 compost and, using a sharp knife, cut away the shoots just above where they join the crown. Trim the stem of the cutting below the joint under the lowest pair of leaves. Carefully remove the leaves, leaving the top intact.
- Dampen the end of the cutting, dip in hormone rooting powder, place in compost and firm in. Use one pot per variety. Cover cuttings with a plastic bag or place in a propagator or a warm place out of direct sunlight. Pot up into John Innes No 2 once rooted. Pinch out the cutting once to make plants bushier.
- Harden off plants before planting outside at the end of May/early June. Slugs and snails love dark-leaved dahlias so frisk plants in the evenings. Destroy any gastropods.
- Stake as you plant, using three canes per plant to create a triangle (each cane about 3ft/1m long). Cap canes and tie two lines of string around them – one higher than the other.
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