The short version: A packet of perennial seed raises dozens of plants where a potted perennial gives you one, but you trade money for time. Most build roots in year one and flower in year two. A few, including Rudbeckia hirta, gaillardia, coreopsis and yarrow, flower in their first summer if sown in late winter. Raise them in trays, check whether the seed needs a cold spell or light, and plant out in autumn or early spring.
Walk past the perennial bench in spring and the arithmetic is obvious. One echinacea in a 14 cm pot is one plant. A packet of seed can fill a whole bed.
The catch is printed nowhere: the pot flowers this summer; your seedlings will not. Our guides to annuals, perennials and biennials and growing annual flowers from seed cover the rest.
Some perennials flower in year one, most wait until year two
Sow these early and keep them growing without a check. Missouri Botanical Garden records Rudbeckia hirta, the black-eyed Susan, as an annual, biennial or short-lived perennial that blooms in year one and is often grown as an annual.
- Gaillardia (blanket flower), quick and untroubled by dry soil
- Coreopsis (Coreopsis grandiflora), fine-stemmed and long-flowering
- Yarrow (Achillea millefolium), tough and flat-headed, but it runs, so contain it
- Some salvias, the bedding types rather than the shrubby ones
- Dianthus, though sweet william (Dianthus barbatus) is a biennial and waits
- Catmint (Nepeta), soft foliage and a long first flush
The rest give leaves in year one and flowers in year two. Echinacea purpurea usually waits, and so do delphinium, Russell lupin and aquilegia, though an early sowing sometimes gives a few late flowers. Hollyhock (Alcea rosea) is a biennial or short-lived perennial that self-seeds enough to look permanent, and foxglove (Digitalis purpurea) is a true biennial: a rosette one year, one spire the next. Both are poisonous, and foxglove cannot lawfully be sown in Tasmania, so read the next section first.
That split sets your sowing date. Sow in late winter to early spring, under cover with warmth, for colour this summer: rudbeckia is commonly quoted at 100 to 120 days to first bloom. Sow in late summer to autumn instead, and the seedlings root through the mild months to flower the next spring.
Check the plant before you sow it
Several are poisonous. The Queensland Poisons Information Centre classes foxglove as extremely toxic, states that all parts are toxic if eaten, and says to seek urgent medical attention if any part is swallowed. Delphinium and larkspur are poisonous too. Ornamental lupin seed is bitter with alkaloids and is not the edible lupin sold as food, so keep soaked seed away from the kitchen, and aquilegia seed and roots are mildly toxic. Wash your hands after sowing, keep packets away from children, and never treat an ornamental perennial as food. The Poisons Information Centre is on 13 11 26.
The second check is weed status. The Department of Natural Resources and Environment Tasmania lists all sexually reproducing Digitalis as declared pests under the Biosecurity Act 2019, and importing, selling, supplying, propagating or spreading them is prohibited, sterile cultivars excepted. We do not send foxglove seed to Tasmania, and Tasmanian gardeners should not sow it. Nothing else is declared, but three are environmental weeds. Yarrow is one in Victoria, the ACT and the New South Wales highlands, and it runs as well as seeds, so keep it from bushland and alpine country and deadhead it. Russell lupin (Lupinus polyphyllus) is one in Victoria and has naturalised on the New South Wales southern tablelands, so cut the pods early. Coreopsis lanceolata is one in New South Wales and Queensland, which is why the list above names C. grandiflora.
A cold spell for some seed, light for others
Cold stratification is a moist chill that breaks dormancy in winter-adapted seed. It is not a general rule. Echinacea and aquilegia respond to it, though the seed still comes up without a chill, more slowly and less evenly. Delphinium wants cool, dark germination and fresh seed kept in the fridge, not a long chill. Rudbeckia, gaillardia, coreopsis, yarrow, salvia, dianthus and catmint need none, and lupin wants soaking or nicking through its hard coat. Our guide to soaking, scarification and cold stratification sorts them out.
To fake a winter, mix the seed through damp vermiculite or coir, just damp enough to clump, and seal it in a labelled container. Refrigerate at around 4°C for four to eight weeks, never the freezer, checking weekly that it is damp and not mouldy. Sow it straight after.
Sustainable Gardening Australia gives the default depth: sow at about twice the seed's width. A few need light and must not be buried: rudbeckia, yarrow and foxglove are pressed onto damp mix and left bare. Delphinium wants the opposite, covered and cool, around 15 to 20°C, while most perennial seed is content at about 18 to 22°C.
Sow into trays, not straight into the bed
- Fill a punnet with fresh seed-raising mix, not reused potting mix. Water it, sow thinly, and cover to the species' depth.
- Bottom water: stand the tray in 2 to 3 cm of water until the surface darkens, then drain. Waterlogged mix brings on damping off.
- Prick out at the first true leaves into 7 to 10 cm pots, holding each by a leaf.
- Grow them on in a bright, sheltered nursery corner for two to four months, potting on as roots fill.
Year one is a rosette of leaves, and that is a success
A rosette of foliage is exactly what an echinacea should be doing in its first summer, building the crown and roots that outlive the annuals beside it. Pinch the tip out of bushy types such as salvia and catmint at about 15 cm. Feed lightly, a half-strength liquid fertiliser or seaweed tonic every three or four weeks; soft growth flops and rots. Do not let them dry out that first summer: mulch around the crowns, not over them, and water deeply rather than often.
Seed-grown perennials vary, and division takes over later
Seedlings are siblings, not clones. Cultivars that nurseries multiply by division or cuttings, which covers most named echinacea and catmint, do not come true from seed. A named seed strain is different: it comes reasonably true, with a spread in colour and height that is a feature in a border and a nuisance in a cutting row.
Seed gets your first plants in numbers, rarely your second batch. Once a clump has a few seasons behind it, dividing it is faster, and taking cuttings suits woodier subjects such as salvia.
Sowing and planting out by climate zone
These are broad groupings, and local frost dates and soil temperature overrule the month. No single authority publishes a month-by-month sowing calendar for the whole country, so treat any as a start.
- Tropical (Darwin in the Northern Territory, Cairns and Townsville in Queensland): wet season humidity rots crowns. Sow in the dry season and lean on gaillardia and salvia.
- Subtropical (Brisbane and the Sunshine Coast in Queensland, Lismore and Coffs Harbour in northern New South Wales): humid summers are the limit, not cold. Sow in autumn into raised, free-draining beds.
- Arid and semi-arid (Alice Springs in the Northern Territory, Broken Hill in New South Wales, Mildura in Victoria, Kalgoorlie in Western Australia, inland and central-west Queensland): sow and plant in autumn. Gaillardia, yarrow, salvia and dianthus take the heat best.
- Temperate (Sydney, Newcastle and Wollongong in New South Wales, Melbourne and Geelong in Victoria at the cold end of the zone): the easiest zone, both sowing windows open.
- Mediterranean (Perth and Bunbury in Western Australia, Adelaide and the Barossa in South Australia): autumn sowing suits the wet winter and dry summer.
- Cool and alpine (Tasmania, Canberra and the ACT, Ballarat in Victoria, Orange, Bathurst and Armidale in New South Wales, Stanthorpe in Queensland): the zone these plants were bred for, and winter stratifies seed for you outdoors. Contain yarrow and lupin here.
Frequently asked questions
My perennials are a year old and have not flowered. What did I do wrong?
Probably nothing, if they are year-two species. Echinacea, delphinium, lupin and aquilegia spend year one on roots. If a year-one species such as gaillardia has stalled, suspect too little sun.
Do I really have to put seed in the fridge?
Only echinacea and aquilegia among the plants here. Four to eight weeks in damp vermiculite at about 4°C, then sow straight away.
How long does perennial seed take to come up?
Longer than vegetable seed, and less evenly. Many take two to four weeks, and some come up in waves. Give a tray double the time a lettuce gets.
Can I scatter perennial seed straight into the garden bed?
You can, and the tougher daisies often oblige, but a tray is safer because the seed is fine and easily lost. Sow direct only into a clean bed that stays damp.
Will the flowers look like the photograph on the packet?
Roughly. A named seed strain comes reasonably true, while a mixed packet is meant to vary. Neither matches a potted cultivar the nursery multiplies by cuttings.
When is the best time to plant my seedlings out?
Autumn, or early spring once frosts have passed: mild weather, moist soil and no heatwave in sight. Plant once the pot is well rooted, water in, and mulch clear of the crown.
Perennials from seed are the slowest thing in gardening, and one of the most worthwhile.
Related growing guides
- Growing annual flowers from seed
- Dividing perennials to revive a tired clump
- Soaking, scarification and cold stratification
Our perennial flower seeds hold yarrow, gaillardia, aquilegia and salvia, and the wider flower seeds range has fast annuals for the gaps.