Cold April delays some blooms, but now the spring show is on

April definitely did not go out like a lamb this year. You probably didn’t put away your sweater until the end of the month, when temperatures finally hit 80 degrees.

Here at the Chicago Botanic Garden, we recorded our coldest April ever since we started recording temperatures in 1982. Our average high temperature in April was 48.1, which is 8.7 degrees below normal.

What did the cold weather mean for our plants?

Luckily, nothing devastating. Early bloomers, like winter aconite, crocus, and snowdrops, weren’t affected, and many bloomed as expected. Those species can also tolerate the colder temperatures we saw in April. If we had seen a few days of high temperatures and some of the more delicate flowers had opened, followed by a subsequent freeze, that would most likely have damaged plants.

May (and later) bloomers are also probably going to arrive on schedule. But plant species that usually bloom in April took their time. Celeste Vandermey, supervisor of plant records, checked to see how late some perennials and trees were this year. On average, most were about two weeks late, with a few outliers taking even longer than usual:

Saucer magnolia (Magnolia x soulangeana) in bloom
Saucer magnolia (Magnolia × soulangeana)

Magnolias: Usually, these start to bloom during the first two weeks of April. This year, we didn’t see flowers start to open until the first week of May.

Nanking cherry (Prunus tomentosa) in bloom
Higan Cherry (Prunus subhirtella ‘Autumnalis’)

Cherries: Mid-April is prime time for cherries here. They have their own festival in Washington D.C. and this year reached their peak there in the first week of April. Our cherries waited until early May.

Red oak (Quercus rubra) leaves emerging
Red oak (Quercus rubra) leaves emerging

Native trees: McDonald Woods is home to many native trees, including oaks and maples, which usually start to leaf between April 8-15. But this year leaves didn’t start to appear until May as well.

Gold Tide forsythia (Forsythia 'Courtasol') in bloom
Gold Tide® forsythia (Forsythia ‘Courtasol’)

Forsythia: Since the Garden began to keep track of first blooms on our grounds more than 25 years ago, this is the latest we’ve ever seen forsythia bloom.

Late bloomers have now all started to exit their winter dormancy. Their tardiness does not mean other species will continue to be late. Once temperatures remain above freezing and the soil warms up, which seems to have begun, most species will do their thing at their expected time. It’s safe to—finally—say spring has arrived.

Redbud (Cercis canadensis) in bloom
Next up: Redbuds
(Cercis canadensis)

Check out the Garden’s What’s in Bloom Highlights every Monday and Thursday for new selections of plants that are putting on a beautiful show, and where to find them.


©2018 Chicago Botanic Garden and my.chicagobotanic.org

Getting That Tropical Look

This season’s Brazil in the Garden exhibition features a bold tropical look at the Chicago Botanic Garden—you can get that same vibrant feel in your home garden, using perennial plants.

Surprisingly, there are a number of plants that thrive in the Chicago area in spite of their tropical looks. With attributes ranging from huge leaves, delicious fruits, or potent fragrances, these trees and shrubs will add a tropical splash to your backyard year after year.

Magnolia ashei is one of the most tropical-looking plants at the Chicago Botanic Garden. It features huge leaves, huge flowers, and huge fruits. The leaves can grow up to 36 inches long, the flowers can be more than a foot across, and the fruits are up to 5 inches long and turn bright red. Magnolia ashei has an irregular growth habit and makes a bold specimen. Look for this one in the Native Plant Garden (however, this plant is not an Illinois native).

PHOTO: Magnolia ashei
Magnolia ashei has beautiful leaves and intriguing fruit.

Another large leaf magolia, Magnolia tripetala x obovata, is similar in most respects; however, it features a broad, round form and is a bit more formal in the landscape. This magnolia can be found in the Waterfall Garden.

PHOTO: Magnolia tripetala x obovata
The blooms of Magnolia tripetala × obovata can be up to a foot across.

Campsis radicans is a native vine with large, orange-red, trumpet-shaped flowers all summer long. The flowers are a hummingbird magnet, which just adds to the tropical allure, and are available in numerous colors, including red, orange, and yellow. This is a large, growing vine so give it room to grow. It does tolerate pruning but blooms best when allowed to grow uninterrupted. Even the seed pods are ornamental, looking almost like green bananas hanging from the flower clusters. Look for it in the Waterfall Garden, and the fence surrounding the Graham Bulb Garden, where we have red and yellow varieties mixed together.

PHOTO: Campsis radicans
Campsis radicans grows in the Waterfall Garden.
PHOTO: Asimina triloba
Pawpaw (Asimina triloba) fruits hang high in the tree.

Another native plant that wouldn’t look out of place in the rain forest is the pawpaw tree (Asimina triloba). This native tree has green leaves that can reach a foot long. It’s a beautiful understory tree that will grow well in dappled shade with ample moisture (but never standing water). However, the real reward with pawpaws are the fruit. These large fruits have an incredibly tropical flavor, like a mix of mango, pineapple, and bananas. The fruit are among the last to ripen in the late summer and well worth the wait. To get a good crop of fruit, make sure to plant two varieties.

Pawpaws also get beautiful golden fall color, which only adds to their appeal. One note of caution however: the trees can sucker, so make sure to plant your pawpaw somewhere where this isn’t a problem, or make sure to remove the suckers as they sprout. Look for pawpaws in the Bulb Garden, Regenstein Fruit & Vegetable Garden, and Native Plant Garden.

And finally, what is a tropical garden without lush fragrances? Clethra alnifolia is a hardy shrub that thrives in partial shade and boasts intensely fragrant blooms in late summer.

PHOTO: Clethra alnifolia 'Rosea'
Clethra alnifolia ‘Rosea’ has cheerful pink flowers that hummingbirds love.
PHOTO: Clethra alnifolia 'September Beauty'
Clethra alnifolia ‘September Beauty’ is one of the latest-blooming summer-sweet cultivars.

Clethra flowers have a rich smell similar to gardenia, but with spicy undertones. The flowers are tall spikes of white or pink and are a magnet for pollinators such as honeybees and hummingbirds. With careful planning, you can mix varieties of clethra and have blooms that last from mid-July through late August. Several varieties of clethra can be found in the Sensory Garden.

See Brazil in the Garden through October 15, 2017.


©2017 Chicago Botanic Garden and my.chicagobotanic.org