If you're anything like me, when you first discover winter sowing, you know just the plants you want to try growing with it. Unfortunately, as versatile and awesome as winter sowing is, it just is not the best way to grow some seeds. Here's a list of great plants to winter sow in Chicago, and terrible plants to winter sow in Chicago.
Perfect Winter Sowing Seeds for Chicago
- Aquilegia canadensis/Aquilegia vulgaris (Columbine) - Columbines winter sow very well. They germinate quickly with the onset of warm weather, and a lot of times you can plant them out by June. The individual plants can be short-lived, but once they're established they self-sow nicely.
- Asclepias incarnata (Swamp Milkweed)/Asclepias tuberosa (Butterflyweed) - both of these plants take very well to winter sowing. Give them at least four months to germinate after the thaw - they're notoriously slow to start, but once they get going they're ready to be planted into the ground by October. The next summer they'll be nearly the size of the plants you see in the nursery.
- Aster spp. Note: this is an abbreviation that indicates the species in a genus. (Asters) - I haven't tried winter sowing Asters myself yet, but reports from other gardeners indicate that they do well, and that most species germinate within a month or two of spring thaw.
- Baptisia australis (Blue False Indigo)/Baptisia sphaerocarpa (Yellow False Indigo) - Baptisia is a slow plant. It sometimes take up to five years to bloom, so for a lot of people it's a much better deal to just go out and buy a plant. Three Baptisia tips: For all Baptisia growers, don't move a mature Baptisia. The plants develop large taproots, which are destroyed in a move or division. They'll normally repay you by not blooming for a year or three. Try to place a Baptisia in a spot it won't have to be moved from in a long, long time. For Baptisia seed growers, Bapstisia can be notoriously hard to start. In reality they're just slow. Keep winter sown Baptisias for at least six months before giving up on them. To help them germinate faster, soak them in a dish of water overnight before sowing.
- Belamcanda chinensis (Blackberry Lily) - Blackberry lilies are slow but steady winter sowers. They can take from one to four months to sprout in spring, depending on how long they were stored, and they can either be planted into the garden their first autumn or kept in pots in a cold, dark place over the winter.
- Echinacea purpurea (Purple Coneflower) - Echinacea does well winter sown. It can sometimes take up to two months to sprout, but once it does it usually bursts into action and is ready to be planted into pots by June, and planted into the garden in autumn.
- Platycodon grandiflorus (Balloon Flower) - Balloon flower grows quickly when winter sown, and some enterprising plants will provide you with flowers before their first year is done. Plant them into pots in May or June, and then either plant into the garden in autumn, or keep the pots in a cold, dark place over the winter.
- Rudbeckia spp. (Black Eyed Susans) - Most garden black eyed susans winter sow well. Many species can take a long time to sprout in spring; my personal favorite, Rudbeckia subtomentosa, took 3 months to sprout the first time I winter sowed it.
Horrible Winter Sowing Seeds for Chicago
- Allium spp. (Chives, Garlic Chives & Alliums) - While Alliums aren't really horrible to winter sow, they do have one big drawback - their seed normally doesn't store well. Allium seed germinates best if it falls directly from the parent plant onto the ground below it. After six months dry, its germination rate is very low, and most Allium seed won't keep if it's stored for more than a year. If you want cheap Alliums, try asking your gardener neighbors for divisions in spring or fall, or get online and trade for divisions through a site like gardenweb.com.
- Delphinium spp. (Delphiniums) - Delphiniums are lovely, lovely plants, but after years of trying to coax them through Chicago's frying summers, I have become jaded. Yes, delphiniums are lovely, and they even winter sow well, but they don't grow well in Chicago or most of the rest of the midwest and I've accepted that. If you absolutely need bright blue in late spring, try Baptisia australis or Centaurea montana (Mountain Bluet). Both will do vastly better than Delphiniums, with much less babying.
- Eupatorium rugosum/Ageratina altissima (Boneset) - I'm going to get on this now because it's a pet peeve of mine - this plant self sows like mad. One year it showed up in my garden, and I waited diligently for the flowers to show me what it was, and then I foolishly let the plant stay over the winter. The next spring there were hundreds of new plants. Hundreds. It's a weeding nightmare, this one. Disclaimer: It grows vigorously in shade (enough to over-run hostas, grumble grumble) and has a pretty (pretty ugly, grumble grumble) dark-leaved morph that many people love (or love to hate, grumble grumble). So sure, it probably winter sows fine. Just make sure to love as much of it as you're going to get.
- Lilium spp. (Lilies) - Lilies are wonderful plants for Chicago, and very fun to grow from seed, but they do better sown by different methods. They can be winter sown, but they're not really "sit them out in the snow and forget about them" seeds. If you're growing lilies for the first time, it's best to start with spring or fall bulbs. Ask for Asiatic or Oriental lilies and pick one you like.
- Lupinus x hybrida (Garden Lupine) - As beautiful as they are, Lupines just don't thrive in the Midwest, whether you buy older plants or start them from seed. Instead, try Baptisia australis (Blue False Indigo) or Baptisia sphaerocarpa (Yellow False Indigo). These take up to 5 years to bloom from seed, so some people prefer to buy plants.
- Paeonia lactiflora (Herbaceous Peonies) - Peonies take from three to ten years to get from seed to bloom. There is no way around that. They do better when they have deep soil to germinate in, and winter sowing just doesn't provide that. In general, if you want to grow peonies, which you should if you are a sane person with sun in Chicago, buy mature roots in fall or mature potted plants in spring.
- Papaver spp. (Poppies) - Poppies do not want you to disturb their roots. Ever. Winter-sown, they must be pried apart by the roots to be planted out, at which point they will promptly give up the ghost. If you've ever bought a potted Oriental Poppy and had it fail on you, there are two reasons why: first, you loosened the root ball before planting it, as is recommended for every other perennial, or, second, you bought it in spring and, as sometimes happens, summer came along. All Oriental Poppies go dormant in summer in Chicago. Their leaves turn yellow and they appear to die. If you wait long enough, and don't dig them up, you'll see their leaves come back up once cool weather resumes in autumn. This happens every year, and most people can deal with it. To hide a bare poppy patch in summer, try perennial hibiscus (in full sun to part sun) or hosta (in part sun to part shade). Either sow poppy seed where you want the plant to grow in the garden, or buy an established plant and don't upset the roots. And, voids forsaken, try not to divide them. [Update 02/13/2011: While you can't really sow poppies in winter sowing containers, you can use cell packs or small pots inside a winter-sowing container to winter-sow poppies. Thanks Monica!]
- Viola x wittrockiana (Pansies) - Theoretically, pansies are perfectly suited for winter sowing. In practice, they just don't grow and flower fast enough before summer sets in and it gets too hot for them to bloom. Instead, sow them in early fall for next-spring bloom, or start them inside in December or January.
I've only included hardy perennials on this list because most perennials need the gentle, caring start that winter sowing provides. (Pansies are perennials - you just have to really pile the mulch on.) Hardy annuals can fend for their own in the garden from the beginning. I'll make another post on them when early spring outdoor sowing time comes around.
This list is only of plants that either A) I winter sowed personally, or B) I had good friends who winter sowed them. This is just a beginner's list, really. Another good beginner's tip: Try to stay under six jugs your first year. You'll get at least ten seedlings out of each jug, that's at least sixty plants! My first year I did 30 jugs. Needless to say, most of those seedlings didn't get planted. Try to plan out what you're gonna do with all those plants.
Procuring perennial seed can be difficult. For your convenience, here is a link to the Dave's Garden Watchdog list of best perennial seed suppliers, ranked from best to worst, most with lots of objective reviews. If you're ever looking into buying from an online garden retailer, check the GWD page for them first.
Finally, I've linked to pages that give a good impression of the plants in question, and a lot of other things. However, they're not the be all and end all of info on gardening. If you want to know how to grow something, google it over and over and over again. Books are also an extremely valuable resource, but garden books tend to be prohibitively expensive. But before winter's over, I'll do a post on my favorite garden books for Chicago. Critique on this list is welcomed, but keep in mind I'm writing from Chicago.