Summer bulbs: plant now (or soon) in WNY

'Tartan' dinner plate dahlia
Dinner plate dahlias get that name because the flowers are large–the flower on ‘Tartan’ can reach eight inches wide and it blooms all summer. The flowers attract butterflies and hummingbirds. These dahlias are easy to grow in moist, fertile soil in full sun, whether you plant them in a garden bed or container. The plant gets to be 36 to 40 inches tall. Photo courtesy Netherland Bulb Company

by Connie Oswald Stofko

Lilies, gladiolus and dahlias are just three of the stunning flowers in a group of plants referred to as summer bulbs.

Patti Jablonski-Dopkin, general manager of Urban Roots Cooperative Garden Market, gives us an overview of summer bulbs and how you can use them in your Western New York garden. Urban Roots, located at 428 Rhode Island St., Buffalo, offers a variety of summer bulbs.

Don’t confuse these with spring bulbs (such as crocus, hyacinth and tulips). Those bulbs must be planted in autumn, two seasons before you see the spring blossoms.

Summer bulbs can conveniently be planted now (depending on your weather and soil conditions) to get flowers this summer.

While we refer to these as bulbs, some are tubers, corms or rhizomes. See more here.

When to plant

You can plant summer bulbs from early to mid-May, Jablonski-Dopkin said, depending on your conditions.

Your last frost date

The last frost varies throughout Western New York and from year to year.

For example, at the Buffalo International Airport, there is a 90 percent probability that April 22 is the last date to have a low of 36 degrees Fahrenheit. However, there’s still a 10 percent chance that there could be a low of 36 degrees as late as May 19. For Jamestown, there is a 90 percent probability that May 4 is the last date for a low of 36 degrees, with a 10 percent chance that June 2 could have a low of 36.

Note: Frost can occur even when the air temperature is above freezing, due to cold air settling, microclimate variations and other factors. Many frosts occur when the air temperature is in the mid-30s.

See the last frost for other WNY areas on the page with U.S. Climate Normals from the National Centers for Environmental Information, part of the National Oceanic and Atmospheric Administration (NOAA).

Soil conditions

The ground should be moist, but not soppy, and the ground should be warm, about 50 degrees Fahrenheit.

“If the ground is too wet and cold, the bulb is going to rot,” Jablonski-Dopkin said.

Here’s a quick test: Scoop up some soil and squeeze it in your hand. If it forms a ball, the soil is still too wet to plant.

Tip: If it looks like the weather is going to be cold and wet, start the bulbs inside in a pot, she said.

Bring summer bulbs inside for winter?

'Blue Moon' gladiolus mix
‘Blue Moon’ is a mixture of gladiolus bulbs that flower in different shades of purple. They are deer resistant and are good for cut flowers. They reach a stately 56 to 60 inch height and are extremely easy to grow in moist, well-drained soil in full sun. Photo courtesy Netherland Bulb Company

There are some summer bulbs that you can leave outside over the winter and others that you have to bring inside.

Winter hardy (leave in ground):

  • Asiatic lilies
  • Oriental lilies
  • Trillium
  • Irises

Tender summer bulbs (bring inside over winter):

  • Dahlias
  • Caladium
  • Canna lilies
  • Tuberous begonias
  • Elephant ears (Urban Roots doesn’t sell elephant ear bulbs, but they will have the plant closer to Memorial Day–elephant ears don’t like cold weather.)
  • Freesia (Many people treat these as annuals and buy the bulbs again the next year.)
  • Gladiolus (Because of global warming, more gardeners are finding that they can leave gladiolus outside in winter if the bulbs are planted in a protected spot, Jablonski-Dopkin said. However, if your gladiolus are in an open area, bring them in.)

The tender bulbs should be dug up at the end of summer when the foliage is dying. Do this before the first hard frost.

If you don’t like digging up bulbs every year, Jablonski-Dopkin understands.

“For so many years, I was going to bring the bulbs in, then a hard frost hits and it’s too late,” she said. “Now I love planting bulbs in pots. It’s nice and easy to bring them inside.”

Here’s another advantage to planting summer bulbs in pots: “You can move them around in the garden if you have a bare spot,” she said.

Plant in clusters

Thalita fragrant lily coutesy
The fragrant double lily Lilium Oriental (Double) ‘Thalita’ has slender stalks topped with a cluster of large, exotic, fragrant flowers. It grows 34 to 38 inches tall, attracts butterflies and hummingbirds, is winter hardy and is great as a cut flower. It needs full sun to partial sun. Photo courtesy Netherland Bulb Company

Whether you’re planting summer bulbs in a garden bed or in pots, don’t plant just one bulb; plant three or more, she suggests, adding that plants in odd numbers look better.

“Any plant looks better in a grouping,” she said.

Another reason to plant multiples of flowers such as lilies, gladiolus and dahlias, is that they are great for using in arrangements.

“If you have one lily, you’re not going to cut the flower,” she said, “but if you plant three or five, you will cut them and bring in a stem to display in a vase.”

When you group your plants, you could arrange them in a triangular formation or a circle.

“Nothing really grows in a straight line in nature,” she said.

A note on lilies

In the past several years, many Western New York gardeners have been discouraged from planting true lilies (Asiatic and Oriental, not daylilies) because of an invasive pest called the red lily leaf beetle. This invasive insect has caused so much damage that some gardeners just pulled up their lilies.

It got so bad that Jablonski-Dopkin hasn’t carried lily bulbs for about four years.

But she is again offering lily bulbs.

“I’ve been hearing from gardeners that things aren’t as bad as they were,” she said. As we heard last year, others are also noticing what seems to be a decline in the numbers of these pests.

If you like lilies, you may want to give them a try this year. You may still have some problems from the red lily leaf beetle, but they might be manageable now. Find out more about red lily leaf beetles here.

If you have lilies, look now for red lily leaf beetles. 

4 Comments on “Summer bulbs: plant now (or soon) in WNY

  1. Hi Belinda, You want room for root development so I would put 1 bulb in at least a 10″ pot. 12″ would be even better. The plant themselves get quite big so you want some weight in your pot so they don’t blow over.

  2. Big powder my lilies work well although not as pretty, I use product called Eight
    Have to catch before they crap or larva all over the leaves

  3. Can dinner plate dahlias be planted in large pot and if so how many bulbs?

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