Self-sowing perennials can be a bonus for your landscape clients and, while vigorous, the selections recommended here will fill in your designs without becoming invasive.


The yellow blooms of ‘Amber Wheels’, with vivid, orange-red eye zones, begin flowering in late May and continue for months.
PHOTO COURTESY OF ALLEN BUSH

There are three good reasons why self-sowing perennials are worth spreading around. The first two are obvious and fit these times of fiscal austerity and sustainability: They’re inexpensive, and they’re renewable. And the third reason, since there are only so many hours in a long, hard day: Self-seeding perennials work while you sleep. The process of becoming blessed with something for nothing is dirt simple. If you allow a few perennial species to seed around capriciously, you get a payback and don’t have to lift a finger. There is no need to worry about legal complications, either. (Patented plants can prohibit generosity since there are restrictions on propagation.) You can pass perennial seedlings along to your pals and won’t have to worry about the heavy hand of the law.

I’ve been a curious observer of garden fecundity for 40 years, but Gary Keim and Larry Hurley deserve credit for recently bringing up the subject of self-sowers. They’ve written in Fine Gardening magazine (www.finegardening.com/design/articles/self-sowers.aspx) and on Behnke’s Nursery blog, respectively (blog.behnkes.com/self-seeding-peren nials-for-the-budget-conscious-gardener.html).

I like Keim’s suggestion to wait before throwing down mulch until you’ve had a chance to thin-out seedlings once or twice. (Do share the extra seedlings with your neighbors.) Hurley mentions reseeding Pulmonaria in Maryland. I should be so lucky!

I fantasize about Himalayan blue poppies, Candelabra primroses, Trollius and Ligularia seeding around in moist meadows. It’s a sweet dream but won’t come true in Louisville, Ky., where I garden; last year we had 84 days above 90° F. And then there are the nightmares! I can smell a menace when seedlings start to germinate in driveway cracks. Any plant that starts to carpet an area with seedlings larger than the floor plan of a small doghouse gets the boot.

So, I am devoting this article to perennials that have been modest self-sowers in Louisville, with no inclination toward invasiveness. (OK, some might be aggressive seeders, but I explain how to deal with that.) I have highlighted some of these and have listed others that have been easy and reliable.

Hellebores

Helleborus foetidus and H. orientalis are good self-seeders in Kentucky. In Louisville, this year, lingering cold slowed their flowering, but by late February, days were growing longer and we had a warm, 10-day reprieve. Out of nowhere, witch hazels, Sarcococca, snowdrops and species crocus tumbled into bloom out of nowhere. These hellebores couldn’t wait any longer. H. foetidus has found a happy home, seeding around in sunnier spots that other hellebores might not find so favorable. Seedpods mature over the next three months. I’ve targeted some specimen plants, originally grown from seed of Jelitto’s Lady Series, that I give special preference to. They remain the mother plants while I deadhead, or pinch seedpods, on others, as they are developing. It is certainly simplest in your client’s home garden to let the seeds fall in the shade of the plant and transplant seedlings the next March or April.

Columbines


Ophiopogon planiscapus ‘Nigrescens’, itself a reseeder, makes a winning companion for perennial columbine.
PHOTO COURTESY OF JELITTO PERENNIAL SEEDS

I have become very fond of Aquilegia canadensis ‘Little Lanterns’. This and its sisters, ‘Pink Lanterns’ and ‘Corbett’, are much more durable in Kentucky than other columbines. Though A. vulgaris types freely seed around, ‘Little Lanterns’ doesn’t give up the ghost after a single season. It goes on for three or four years, and spreads its seeds around my scree garden for future generations. ‘Little Lanterns’ is a little version of the species and grows only 8 to 10 inches tall. A nice combination with any of these columbines is the black foliage of the low-growing monkey grass Ophiopogon planiscapus ‘Nigrescens’ – another reseeder. The soft bluish blooms are a bonus.

Foxgloves

Gardeners looking through glossy catalogs might skip over Digitalis lutea in favor of showier and larger flowering foxgloves. I love these, too, but D. purpurea types are gone in the blink of an eye. It’s a wonder they make it to the first of July. D. lutea has smaller, pale yellow blooms and neat rosettes of dark green, lance-shaped leaves. I planted my first plants 16 years ago, and this species hasn’t skipped a beat in our heat and humidity.


Often overlooked in favor of its showier blue cousins, Digitalis lutea outperforms them in its longevity.

Blanket flowers

Gaillardia aristata ‘Amber Wheels’ is a Jelitto introduction that comes back. Repeat: It comes back! They casually self-sow around the scree, and they always provide a few extra seedlings to pass along. The yellow blooms of ‘Amber Wheels’, with vivid, orange-red eye zones, begin flowering in late May and continue for months. Many seed strains, and newer patented selections, might as well be treated as annuals or biennials – not ‘Amber Wheels’.

Hollyhocks

I’ve always had a soft spot for Alcea species. I love them in spite of their shortcomings, including rust and Japanese beetles. My colleague Georg Uebelhart (at Jelitto’s headquarters in Germany) taught me a simple rust-prevention technique. Cut back the first flush of leaves – straight to the ground – in April, and the incidence of rust is significantly reduced. The Japanese beetles are no longer such a problem here in Louisville, as the digger wasp, a natural predator, parasitizes the larvae. I’ve planted the lovely, single-flowering ‘Spotlight Series’ – available in individual colors of dark black-purple, red, yellow and white with a yellow eye – and let nature do the rest.

Small wood sunflowers

Helianthus microcephalus ‘Lemon Queen Strain’ has been a constant for 10 years. It’s big (to 72 inches), surely qualifying for Garden Giant status, but I sometimes cut back the foliage by one-half in early June to shorten the height. (I’m not sure why.) You don’t need to be so fussy. The simple pale-yellow blooms are arresting.


Helianthus microcephalus ‘Lemon Queen Strain’ can grow to 72 inches tall, but may be cut back to control its height.
PHOTO COURTESY OF ALLEN BUSH

The native Coreopsis tripteris is a rather tall selection worthy of inclusion in a client’s garden.
PHOTO COURTESY OF JELITTO PERENNIAL SEEDS

Reliable self-seeders

Besides what easily self-sows in our Kentucky gardens (my colleague Mary Vaananen also gardens here), I asked my European colleagues to list what’s coming-up in theirs. Georg Uebelhart, Jelitto’s general manager, gardens in Salzhausen, Germany – between Hamburg and Hannover. And Richard Oliver, manager for the United Kingdom and Ireland, gardens in Huntingdon, Cambridgeshire, England.

Kentucky

Alcea (May-October)

Alyssum (Aurinia) saxatile (April-May)

Aquilegia canadensis ‘Little Lanterns’ (April-May)

Carex comans bronze form (May)


Northern sea oats may be considered an aggressive self-sower, but removing the seed heads in fall will impede the plant’s spread. And the harvested stalks make a beautiful, seasonal addition to indoor flower arrangements.
PHOTO COURTESY OF JELITTO PERENNIAL SEEDS

Chasmanthium latifolium (July-August)

Coreopsis tripteris (July-September)

Digitalis lutea (May-June)

Echinacea (June-August)

Eupatorium (July-September)

Gaillardia aristata ‘Amber Wheels’ (May-September)

Helianthus microcephalis × ‘Lemon Queen Strain’ (July-August)

Helleborus foetidus and Helleborus orientalis (February-April)

Lilium formosanum (August-September)

Ophiopogon planiscapus ‘Nigrescens’ (May-June)

Scutellaria indica v. parviflora (May-June)

Silphium (June-August)

Stipa (Nasella) tenuissima (June-August)

Vernonia (July-September)


To prevent Silphium from becoming too aggressive, the blooms may be deadheaded once they fade. A few seed heads may be left to spread the wealth.
PHOTO COURTESY OF ALLEN BUSH

England

Arabis ferdinandi-coburgi ‘Old Gold’ (April-May)

Calendula officinalis (May-July)

Corydalis (Pseudofumaria) lutea (April- May; then September)

Erigeron karvinskianus (May-November)

Euphorbia amygdaloides ‘Purpurea’ (Rubra) (April-May)

Euphorbia myrsinites (May)

Geranium bohemicum (May-June)

Gypsophila repens (May-October)

Helleborus foetidus and H. orientalis (February-April)

Hemerocallis varieties (June-July)

Kniphofia (June-September)

Leucanthemum hosmariense (April-November; sometimes every month of the year)

Miscanthus sinensis (July-September)

Panicum virgatum (July-September)

Papaver orientale ‘Brilliant’ (June)

Penstemon mexicale ‘Sunburst Ruby’ (May-September)

Phalaris arundinacea (August-September)

Potentilla thurberi ‘Monarchs Velvet’ (June-July)

Rudbeckia maxima (August-September)

Stipa gigantea (May-June)

Vernonia bonariensis (July-October)

Viola odorata (March-April)

Germany

Allium schoenoprasum (May-August)

Aquilegia vulgaris (May-June)

Campanula persicifolia (June-July)

Chrysanthemum leucanthemum (Leucanthemum vulgare) (May-September)

Corydalis lutea and Corydalis ochroleuca (May-September)

Eranthis hyemalis (February-March)

Erigeron karvinskianus (June-October)

Euphorbia cyparissias (June-July)

Galanthus nivalis (February-April)

Geranium pratense (June-August)

Hyacinthoides (Scilla) non-scripta (May)

Lychnis coronaria (July-August)

Meconopsis cambrica (June-September)

Papaver alpinum and P. nudicaule (June-August)

Papaver rhoeas and P. somniferum (May-August)

Thymus serpyllum (May-September)

Tiarella polyphylla (April-September)

Tradescantia (May-August)

Verbascum phoeniceum (May-August)

The big guys

I’ve got to toss in four of my favorite Garden Giant Reseeders. It’s no secret that growers can stack more short plants on shipping carts headed to garden centers than big ones. This makes great business sense but shortchanges gardeners. You can – and should – stand up and reverse the flow with Coreopsis tripteris, Silphium, Vernonia and Eupatorium. If any fault can be found with this quartet, it would be that they can be aggressive seeders, but they’re native, so they get a pass. I routinely deadhead these following flowering, especially the Silphium, though I’ll leave a few seed pods that will spread ample wealth.

Though half the size of the Garden Giant plants, northern sea oats – Chasmanthium latifolium – is an aggressive self-sower, too. Aggressive is code to gardeners similar to the liquor industry’s advice: Drink Responsibly. Too much of a good thing, and you may pay a price. So with Chasmanthium, you should plant these in wild areas where they can binge all they want. Or judiciously deadhead plants in late summer and early fall. The seed heads are vase-friendly and make great additions to bouquets.

Lilium formosanum is big and tall, but I don’t think of it as a Garden Giant Reseeder. It is thin as a rail, and it stretches to 8 feet tall in rich soils. The big, white, late summer trumpets stand regally above the littler plants that had been crammed onto tight shipping racks only months before. The Formosa lily comes with a fall and winter bonus: The parchment-like seed heads are decorative until the next March.

Self-sowers do require a gardener’s latitude to germinating plants in peculiar places. In my earliest gardening years I thought I could control my garden destiny, but that was a hopeless endeavor. I learned, after a few years, that every day was a new surprise. Bugs and droughts sometimes seemed near Biblical, but how enchanting it is to have a few perennials pop up from nowhere.

Allen Bush is director of special projects for Jelitto Perennial Seeds, Louisville, Ky. He can be reached at allenb@jelitto.com.