Home Propagation Easy perennials from seed

Easy perennials from seed

Save and grow hard-to-find varieties

Many gardeners are happy to sow annuals or biennials from seed but prefer to buy perennials from a nursery or garden centre.

There’s a myth that perennials are hard to grow, yet most need very little heat, or skill, to germinate, you can save a fortune and grow much rarer plants.

The majority of my seed-sown perennials came from Plant World Seeds‘ Coloured Foliage Collection in 2015, really good value at £14.95 – Geranium Purple Haze, Haloragis Wellington Bronze, Heuchera Metallica, Lavatera arborea variegata, Nicandra Splash of Cream, Penstemon Husker Red, Phormium Mixed and Plantago major rubrifolia.

Occasionally there are substitutes, but that’s half the fun. I didn’t grow them all, but here are the ones that I did:

  • Geranium pratense Purple Haze: 60-75cm. Foliage with a bronze-purple hue, deepest in shade during spring, gradually changing to deep green with purple edging. Violet-mauve blooms.
  • Heuchera Metallica: 40cm. Marbled and veined leaves in mahogany, bronze, aluminium, and silver, most distinctive on young spring foliage. Flower sprays in pink and white.
  • Lavatera arborea variegata: 1.2m. This variegated tree mallow has irregular splotches of cream on big, downy leaves. Purple flowers smother the plant in early summer. Some doubt over its winter hardiness, but it survived its first winter here.
  • Penstemon Husker Red: 60-90cm. Beetroot-coloured stems and foliage with rosy-lipped, palest pastel pink tubular flowers.
  • Plantago major rubrifolia: 40cm. A deep purple form of the giant plantain, with large, shiny purple leaves producing an impressive rosette, from which arise long thin poker-like seed heads. Great ground cover and will stand some shade.
  • Agastache Golden Jubilee: 50cm. This hyssop is exceptional for its lush rich yellow-chartreuse, mint-scented foliage and blue-lavender bottle-brush flowers throughout the summer. Best if given a bit of shade to protect the foliage colour.

These three were separate packets from Plant World Seeds.

  • Hardy Geranium Mixed: 30-90cm. Containing varieties with too few seeds to list on their own and a few rarities. £2.95.
  • Euphorbia Mixed: 45cm-1.2m. Hardy perennial Euphorbias, including some unnamed rarities. £2.95.
  • Penstemon lyallii: 45-60cm. From Idaho/Montana. A compact overwintering rosette sprouts forth many branching stems heavily laden with large, slightly squashed, pink-lavender flowers. £2.25.

And these were sown in 2016:

  • Foxglove Candy Mountain: 90-140cm. The first upward facing foxglove from seed with rose pink blooms and freckled throats. £2.99, Thompson & Morgan.
  • Foxglove Summer King: 60-90cm. The flowers are very large, strawberry-rose in colour withdarker markings on the inside. Usually lives 2 to 4 years. A naturally occurring cross between the yellow flowering Digitalis grandiflora and Digitalis purpurea. From Sophie Conran’s Wildflower Garden Seed Set by Burgon & Ball, £9.95 (also contains Antirrhinum majus Royal Bride, Centaurea dealbata and Cosmos Sweet Sixteen.
  • Aquilegia Green Apples: 30cm. Clematis-like flower formation, the buds open in a lime-green shade, fading to apple-green before ageing to cream. £2.99, Thompson & Morgan.

potted-guide-logoPotted guide: sowing perennials

Plant World Seeds’ sowing advice on perennials:

  • Sow seeds on to a good soil-based compost and cover with fine grit or compost to approximately their own depth.
  • They can be sown at any time, and although germination can be quicker if kept at 15 to 20 degrees C, we sow most seeds in an unheated greenhouse and wait for natural germination, as many seeds wait for spring before emerging regardless of when they are sown.
  • Spring sowing will obviously give them a full season of growth.

Perennials with different needs

Here’s two which require different treatment:

  • Dianthus deltoides Alba (white maiden pink): 15cm. Forms a dark green mat and stands some shade, with white, starry flowers. It needs a cold spell in wet compost to break dormancy, so sow in winter or early spring. Cover seeds very thinly with sand or fine grit. If the seeds do not come up within six-12 weeks, the seed tray can be put in a fridge for about four weeks. They may still take many months to appear, but mine did eventually.

  • Cynara cardunculus (cardoon): 1.5m+. A relative of the globe artichoke, with edible stems when cooked. Huge divided silver leaves and big thistle-like ‘flowers’. mine came from a 49p packet. Sow from January individually in 7cm pots for planting outdoors after the last frost. Place in a propagator at between 21-24C, then grow on in cooler conditions under glass when germinated. Move into a cold frame (without heat) for six-eight weeks before planting out. Plants grow slowly at first and should be transplanted into a larger container before moving to their permanent positions.