Archives For Horticulture & Display Gardens

Learn more about the plants and gardens at the Chicago Botanic Garden.

We’ve officially reached planting season, and it is now safe to put in warm-season flowering annuals, vines, herbs, and vegetables. Horticulturists at the Chicago Botanic Garden do recommend waiting until Memorial Day for cold-sensitive plants such as tomatoes, peppers, eggplants, and squash. Happy planting!

Summer plantings await in the Production Greenhouses.

Summer plantings await in the production greenhouses.


Looking for a challenge? Try these techniques from our blog and the Smart Gardener:

Diascia Barberae 'Flirtation Pink'.

Diascia barberae ‘Flirtation Pink’

Get the best performance from your plants with these tips from the Garden’s Plant Information Service:

  • Pinch back one-third of new growth to encourage stocky habit (except vines).
  • Be sure newly purchased annuals have been hardened off properly before planting them outside. That means moving plants outdoors for a portion of the day to gradually introduce them to the direct sunlight, dry air, and cold nights.
  • Avoid fertilizing newly planted annuals for two weeks.
  • Continue to plant new perennials, ornamental grasses, and roses in containers. If plant roots are root-bound (encircling the pot), make four cuts into the bottom of the root ball with a sharp tool, and flare the sections outward when planting.
  • Stake tall perennials before they reach 6 inches. Begin to regularly pinch back fall-blooming perennials such as chrysanthemums, asters, and tall sedums. Pinch once a week until the middle of July. This promotes stocky growth.
  • Continue to direct the growth of perennial vines on their supports. Climbing roses should be encouraged to develop lateral, flower-bearing canes.
  • Let spring bulb foliage yellow and wither before removing it. The leaves manufacture food that is stored in the bulb for next year’s growth. Even braiding the foliage of daffodils can reduce the food production of the leaves.

Our monthly checklists and Plant Information Service have a host of other gardening tips—including care for lawns, shrubs, and roses.


Photos by Bill Bishoff
©2016 Chicago Botanic Garden and my.chicagobotanic.org

Attention orchid fans: our vanilla orchid is blooming in the Tropical Greenhouse at the Chicago Botanic Garden. It’s a rare occurrence in the wild—and in a greenhouse. Wade Wheatley, assistant horticulturist, seized the moment to hand-pollinate the flower. 

Vanilla planifolia before pollination

Vanilla planifolia before pollination

Why hand pollinate? In hopes of producing a vanilla bean. Yes, the fruit of a vanilla orchid is used to make pure vanilla extract, which flavors many foods we enjoy.

Vanilla vines typically begin to flower at five years or older. Flowers are produced in clusters, with one flower opening each day in the morning. Stop by the Tropical Greenhouse soon to see what’s in bloom. 


©2016 Chicago Botanic Garden and my.chicagobotanic.org

It is our responsibility as citizens, but especially as practitioners in the fields of horticulture and botanical sciences, to be good stewards of the land and ensure that what we are growing in our backyards and at the Chicago Botanic Garden will not contribute to problems in the future. That is why the Garden recently replaced the callery pears at the entrance to the Visitor Center.

In addition to the callery pear, the Garden also removed winged euonymus (Euonymus alatus) and tamarisk (Tamarix spp.).

Callery pear and euonymous plantings at the Visitor Center entrance in autumn of 2010.

Callery pear and euonymus plantings at the Visitor Center entrance in autumn of 2010.

One threat to our natural world is invasive plants. While many of these plants may on the surface appear to be attractive additions to the landscape, they can force out native species. Short of complete destruction of a natural area, I cannot think of anything more unsightly than a natural area that has been completely consumed by an invasive species to the point that it is no longer recognizable and holds very little biodiversity.

The list of invasive plants and potentially invasive plants is not set in stone; it is an evolving list and one that will continue to change as our climate changes. The callery pear (Pyrus calleryana) was not on the invasive species lists for our region a decade ago, but today it is in Illinois, along with Alabama, Georgia, South Carolina, and Tennessee. Most are familiar with the cultivar ‘Bradford’, but there are several others, including ‘Aristocrat’, ‘Autumn Blaze’, and ‘Cleveland Select’.

Garden staff plant non-invasive American yellowwood (Cladrastis kentukea) at the entrance to the Visitor Center.

Garden staff plant non-invasive American yellowwood (Cladrastis kentukea) at the entrance to the Visitor Center.

This spring we replaced all of the Pyrus calleryana ‘Autumn Blaze’ at the front entrance of the Visitor Center with the non-invasive American yellowwood (Cladrastis kentukea). As a result, the front entrance is noticeably more open in appearance, and the low canopy and refreshing shade that existed in years past is now gone; it will return as the plantings grow.

Although both of these species are medium-sized deciduous trees with white flowers, the yellowwood has different ornamental characteristics. The callery pear flowers in the early spring, while the yellowwood flowers in late spring to early summer. The callery pear has unrivaled fall color in shades of red, orange, and yellow, while the yellowwood is one of the best for yellow fall color. 

Why is the callery pear called an invasive?

This pear has abundant seeds that can be carried by birds to natural areas. Plants can then become established, thus displacing native species. As land stewards, the Garden is very mindful of prohibiting and eliminating any plants known to be invasive in our region.

The new plantings at the Visitor Center entrance.

The new plantings at the Visitor Center entrance will take time to grow, but will someday provide the shade and fall color of their predecessors.

I have no doubt that some of these recently removed invasive plants were favorites among Garden visitors, our staff included. But sometimes what we like isn’t always good for us, or good for the environment.

New seasonal plantings replace the previous shrubs in the entry beds.

New seasonal plantings replace the previous shrubs in the entry beds.

I encourage you to review and continue to consult invasive species lists, including on the invasive.org website, and do your part by removing invasive species from your garden and resist purchasing and adding more. There are so many benign, beautiful options available to gardeners, and the Garden, along with numerous other organizations, has done the work for you by listing alternatives for the invasive plants that we feel we cannot live without. View a list of our recommended alternatives to invasive plant species here

Each of us can play an important role in preserving the natural landscapes for future generations.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

With the Kentucky Derby—and mint julep season—approaching, it’s time to consider mint, a fast-growing, almost wonderfully invasive plant.

PHOTO: Spearmint in bloom.

A refreshing digestive, mint can be harvested more than once in a season; use it fresh in your mojito, or dried as tea.

Mint survives Chicago winters and comes back hardier than ever. Cuttings easily take root and begin propagating anywhere they touch soil. For these reasons, grow mint in a plastic pot, so it doesn’t take over your yard. (The roots are so strong they can crack clay pots.) Mint needs at least four hours of sunlight per day, so pick a sunny spot. It is tolerant of most soils and weather conditions—just be sure it gets some water every week to keep it from becoming bitter.

Maintaining flavor

Mints spread in two ways: by runners and by seed. However, many plants are hybrids, which means the sprouts that shoot up from the broadcast seed will probably not be the same as the plant you bought. To keep that lovely flavor you brought home, trim the plants down when they have flowered, but before they drop seed. This causes the plant to bush out and spread from the roots only.

Choosing your flavor

PHOTO: Mint julep by Bill Bishoff.

Mmm-Mmm mint julep—a Kentucy Derby favorite! Photo by Bill Bishoff

There are more than 600 types of mint on the market. Here are a few that work best in the kitchen:

Kentucky Colonel spearmint (Mentha spicata ‘Kentucky Colonel’) got its fame from being the leaf of the classic mint julep, but it’s also perfect for any mint sauce or jelly.

Banana mint (Mentha arvensis) is part of the spearmint family, but grown mostly for its incredible smell. It still maintains a good flavor in cooking, though.

Peppermint (Mentha piperita) is most often used for its peppermint oil. Peppermint family plants are strong flavored and best used dried or in small quantities because they contain menthol (think Vicks). They soothe stomachs, but are difficult to cook with fresh.

Variegated pineapple mint is a lovely, sweet-scented peppermint hybrid that makes a great tea. To keep it variegated, you need to cut off any green stems.

Orange mint is the most invasive of all mints, so plant accordingly. It smells sharply of orange peel and can turn a nice burgundy color during winter It also works beautifully in baking recipes.

Easy Mint Simple Syrup

PHOTO: Mint simple syrup.Making simple syrup is a great way to put your mint to good use.

What you need:
½ cup mint of your choice (washed leaves; lightly chopped pieces packed down)
1 cup water
1 cup sugar

Directions:
Rinse and drain mint leaves. Bring water to boil in a small pot on the stove. Add mint leaves and sugar. Stir until sugar dissolves, and then turn off heat. Let mixture cool (approximately 30 minutes). Strain off leaves.

Store the syrup in the refrigerator for use within two weeks, or freeze for later use.

To use:
Add this simple syrup in place of sugar in your favorite ice cream, sorbet, lemonade, soda, or cocktail to add balanced mint flavor to any recipe. Even better, add to a dry wine or prosecco for an easy happy hour treat.

Want to take it higher? Freeze the syrups in ice cube trays with a few small leaves and use as a sweetener for tea or cocktails. A glass of bourbon becomes a Mint Julep when you add Mint Syrup ice cubes.

Peppermint Extract

PHOTO: Peppermint extract.Peppermint oil is often used for cleaning, pest control or aromatherapy. What you produce is not the professional essential oil (that takes more time and effort than most of us can muster), it will do the jobs needed.

What you need:
A sealable/airtight jar or glass container
Enough chopped peppermint or peppermint family leaves to fill the jar
Vegetable oil, olive oil or nut oil 

Directions:
Place washed chopped mint leaves in the container (no need to pack; they need to breathe a bit). Heat the oil of your choice (use enough to fill the jar) on the stove in a small pan until it is too hot to touch. Pour the oil over the leaves and seal the container. Let the mixture sit on the counter until it has cooled, then move it to a dark place or cupboard for a week and a half to two weeks. Once it has set, strain out the liquid into a spray bottle.

Uses:
Peppermint oil sprays are said to prevent mold and can be mixed with vinegar to create a simple disinfectant cleaner. They also create a great air freshener, massage oil, or natural control against ants, mosquitos and even rodents.

PHOTO: Tarragon simple syrup and fresh peaches enliven a sparkling wine cocktail.

Add simple syrup to Prosecco and peaches: lovely.

Want to save more of the amazing herbal flavors in your yard this year? Check out our post on Herbal Mixology for ideas.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Did the striking Silver Fox foxglove make it into “the show” this spring? Who decides which flowers make the cut anyway for the unfurling of 75,000 annuals at the Chicago Botanic Garden?

We’ll show you a few of our spring favorites that made it through the multi-level review process.

Digitalis purpurea ssp. heywoodii ‘Silver Fox’

Digitalis purpurea ssp. heywoodii ‘Silver Fox’ (Sensory Garden)

“Behind all of these beautiful displays, there is a lot more happening than what you may think,” said Tim Johnson, the Garden’s senior director of horticulture. “It can be very complex—different plants have different production times.” Besides considering how long it takes for a plant to grow in our greenhouses, the Garden’s experts also consider the desired size and bloom time.

Every season, each horticulturist proposes a color scheme and submits plans to Johnson. About ten months before spring or the start of the other seasons, the proposals are reviewed by experts, including Kris Jarantoski, executive vice president and director; Tim Pollak, outdoor floriculturist; Brian Clark, manager of plant production; Andrew Bunting, assistant director of the Garden and director of plant collections, and Johnson. The team also considers how each proposed plant fits into a garden’s design and color scheme, along with its habit, culture, and cost. “They all need to be looked at globally to make sure there are different plants, varieties, and color schemes throughout the entire Garden,” Johnson said. “Each garden should have a unique look to it.”

Viola 'Fizzy Grape' by Ball Seed

Viola × wittrockiana ‘Fizzy Grape’ (Lake Cook Road entrance and gatehouse)

Primula vulgaris ‘Primlet Golden Shade' by Panam Seed

Primula vulgaris ‘Primlet Golden Shade’ (Heritage Garden troughs)

Hyacinthoides hispanica 'Excelsior' by Brent & Becky's Bulbs

Hyacinthoides hispanica ‘Excelsior’ (Heritage Garden troughs)

Ranunculus asiaticus Maché 'Purple' by Ball Seed

Ranunculus asiaticus ‘Maché Purple’ (Green Roof)

Linaria maroccana 'Licilia Peach'

Linaria maroccana ‘Licilia Peach’ (Circle Garden)

Calendula officinalis 'Neon'

Calendula officinalis ‘Neon’ (Sensory Garden)

Dianthus barbatus ‘Sweet Purple’ by Panam Seed

Dianthus barbatus ‘Sweet Purple’ (Sensory Garden)

Tulipa 'Amazone'

Tulipa ‘Amazone’ (Crescent Garden)

Before spring slips away, come see what’s in bloom at the Garden and look for the annuals that made the final cut, including—you guessed it—an unusual foxglove known as ‘Silver Fox’. Before you visit, download our free GardenGuide app to help you find plants.


©2016 Chicago Botanic Garden and my.chicagobotanic.org