Growing Perennials from Seed: Five Easy Species

by Karen Bovio, owner, grower, Specialty Growers nursery, Howell, MI

Now is the time of year that gardeners start to think about growing some plants from seed. If you've grown tomatoes and peppers from seed and found the experience rewarding, you might like to experiment with annuals and perennials from seed. (My top 5 for you...)

Perennials have a reputation for being finicky and hard to grow from seed. While it is true that some types have demanding germination requirements, many are quite easy and don't require a lot of special equipment. 

Cultivars not a good bet. Choose big seeded fast growers

It's important to understand that not all perennials can be grown from seed. Most named cultivars are complex hybrids, and will not "come true" from seed. Some cultivars do not even produce viable seed. Still, seed catalogs are filled with choices of perennials to grow from seed.

Often the germination tips in catalogs are brief, and little is said in regards to size of seed, length of time to germinate, or how long it takes to get a good-sized transplant that is ready to be planted outdoors. If you're new to seed starting, it's best to choose varieties that have relatively large seeds, germinate without elaborate temperature regimes, and grow quickly. Fortunately there are many that meet those criteria, including:

Gaillardia (blanket flower)
Dianthus (pinks)
Baptisia (false indigo)
Delphinium
Heliopsis (false sunflower)

Prerequisites: Sterile soil-less mix and good light

Before discussing a few of my favorite choices, I'd like to stress the importance of using a sterile soil-less mix, specifically designed for seed starting. Do not use common potting soil, which may be too heavy, and may not be sterile. Seedlings are very susceptible to damping off diseases that may be carried in soil.

It is also necessary to have a good source of light. While it is helpful to use a fluorescent light set-up, a south window will suffice. As a rule of thumb, perennials have lower temperature requirements for germination than hot-season veggies and herbs like tomatoes, eggplants, and basil. Sixty to sixty-five degrees is usually fine, and many will germinate with even lower temps - they'll just take longer. If you have an electric heat mat, by all means use it, but it is not necessary for the varieties I've listed.

Gaillardia grandiflora varieties - Blanket Flower

These are super-easy to grow from seed. The seed is rather large, making it easy to handle, and germination is quick - usually within 2 weeks. The seedlings grow fast, and are quite sturdy, so they're easy to transplant. You can start them directly in cell-packs (you can wash and sterilize packs that you already have from purchased annual or vegetable transplants), peat pots, or simply sow in a shallow tray of germinating mix.

The Arizona Series ('Arizona Sun', a bicolor of red and yellow, 'Arizona Apricot', and 'Arizona Red Shades') are readily available in seed catalogs or online seed merchants. In the garden they grow about 12" tall and are suitable for full sun and well-drained soil.

Let me emphasize that: Gaillardia does not fare will in rich, moist soil. They need excellent drainage in the garden. Keep them on the dry side as a seedling too, to avoid root rots. If you are looking for a lovely long blooming cut flower, try one of the older varieties, such as 'Burgundy' or 'Dazzler' which grow to 24" and produce plenty of long-stemmed flowers for bouquets.

Dianthus species - Pinks

There are many kinds of Dianthus that can be grown from seed, and all are easy.  Cheddar Pinks (D. gratianopolitanus), Alpine Pinks (D. alpinus), Sweet Williams (D. barbatus) and Maiden Pinks (D. deltoides) are all species for which seed is readily available. The seed is rather small, but not so small as to be difficult to handle.

Fill some peat pots with dampened germinating mix, water to settle the mix, and let drain for a few hours. Sprinkle a few seeds on top, and cover very lightly with dry germinating mix. Use a sprayer filled with water to wet them down, then cover with a piece of kitchen plastic wrap. Dianthus seedlings usually geminate in 7 to 10 days.

Uncover when they have germinated, then grow them in strong light.  Thin each pot to the strongest one or two seedlings. Dianthus likes cool temperatures once grown, so they can be hardened off in late April, and planted outdoors without fear of frost damage. You'll find that candyfuft (Iberis sempervirens) can be grown the same way, and they do well together as companions in the garden.

Baptisia (Baptisia australis) -False Indigo

Here's a stately perennial that you might pay big bucks for at a garden center, but you can easily grow the basic Baptisia australis from seed (not the fancy new cultivars, which must be propagated by tissue culture, cuttings or division). You can even use collected seed which you harvest from the inflated black pods that form in mid to late summer.

Baptisia is a legume, which means it has rather large, bean-like seeds. For best germination, rub the seed on a piece of sandpaper (to lightly scratch the surface - but not so hard that you rub off the seed coat) and soak the seed in warm water for a few hours before sowing.

You can sow into any container, and despite warnings that legumes don't transplant well, I have found that when transplanted while still small, they do not suffer.

Although the seedlings might seem slow growing, they're simply putting more energy into growing a tap-root than visible aerial parts. Once planted in the garden, that taproot makes the seedlings remarkably drought resistant. Within 2 or 3 years you'll have a big blooming plant.

Lupine (another legume) is perhaps even easier to germinate and grow from seed, but in our hot and humid summers they are not nearly as long-lived in the garden as Baptisia.

Delphinium (tall Delphinium elatum and others)

Gardeners love delphiniums, but hate putting out money year after year when they fizzle out in the garden. If you grow them from seed, you'll save lots of money, and in our experience, the young seedlings establish much better in the garden than large nursery plants. Delphiniums do not have a great germination rate - sometimes it is less than 60%, so sow the whole packet. You can then pick out the strongest ones to save, or give any surplus away to friends.

Delphinium is amazingly cold-tolerant as a young plant. They will do just fine on a cool window sill, and can be hardened off quite easily. That makes them ideal to plant during the cool month of April so they'll be established in the garden before summer heat arrives.

Seed is medium sized, and should be covered just barely with soil mix to germinate. References vary about the best germination temperature. Some say around 55 degrees, others say upwards of 70 degrees. I have had excellent results with temps between 65 and 75 degrees.

Heliopsis- False Sunflower

Recent interest in native plants is causing gardeners to take a second look at this big, easy plant. Tall as a Phlox, blooming for a very long time, and attractive to bees and pollinators, Heliopsis helianthoides is a great addition to the back of the border or for use in large gardens.

It is very easy to grow from seed. You'll find two varieties commonly offered. The first is 'Summer Sun', old as the hills and tried and true, with single to semi-double golden daisy-like flowers. 'Summer Nights' is a somewhat newer variety that has variable flowers, many with orange centers, and dark foliage and stems.

They're a cinch to grow in peat pots, and can also be sown directly into trays and transplanted. The large seed is easily handled, as are the sturdy seedlings.  Germination is easy and fast - usually within 14 days. Like true sunflowers, Heliopsis likes full sun and rich soil. Like tall Phlox, keep them widely spaced in the garden to prevent powdery mildew.