Archives For Horticulture & Display Gardens

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

What comes to mind when conceptualizing a new garden design? Color? Absolutely. Soil and sun conditions? That’s a given. Texture? Sure thing. Two other components of plant selection that are of utmost importance are adding biodiversity and sustainability. Both of these elements are omnipresent in gravel gardens.

The origins of gravel gardening are rooted in Essex, EngIand, via Beth Chatto, Cassian Schmidt at the Hermannshof Garden in Germany, and Roy Diblik of Northwind Farm in Wisconsin. I was introduced to gravel gardens while I lived in Madison, Wisconsin. Not only were gravel gardens featured at Olbrich Botanical Garden, but they were also on display at my previous place of employment, Epic Systems, in Verona, Wisconsin. Jeff Epping, the director of horticulture at Olbrich, established the gravel gardens at both Olbrich and Epic Systems, and has been very supportive in my mission to bring these types of gardens to the Chicago Botanic Garden.  

The heavy, clay-laden soils of the Chicago area are infamous to anyone who has gardened here. No one escapes the frustration the water-retaining properties of these soils causes. Midwestern gardeners often amend the soil in their home gardens. But amending soils in garden beds each season to improve plant health and drainage can also be an expensive endeavor for the home gardener.

The first step in prepping the beds: removing the top layer of soil.

The first step in prepping the beds is removing the top layer of soil.

This season, as a trial, we are converting ten island beds in parking lot 1 to gravel garden beds. These beds are covered by 4 to 5 inches of pea gravel. The gravel allows plants to grow in sharp drainage, which is a very desirable attribute when growing many native prairie plants or other dry-loving plants. Ours include coneflower  (Echinacea paradoxa), ‘Siskiyou Pink’ beeblossom (Gaura lindheimeri ‘Siskiyou Pink’), and ‘Red Rocks’ beardtongue (Penstemon x mexicali ‘Red Rocks’).

The key to establishing the plants in a gravel garden is to prevent the root balls from drying out until they have a chance to root down below the gravel layer. This means watering new plantings daily, or even twice daily if weather conditions dictate. Although a significant commitment to watering is required up front, watering can be reduced six to eight weeks after planting, and nearly eliminated after two years. In fact, with the exception of times of extreme drought, no supplemental watering was necessary for the gravel garden beds I managed at Epic Systems.

Gravel garden plantings include succulents and drought-hardy plants.

Plantings include succulents and drought-hardy plants. They will need careful monitoring at first, but once established, this bed will be a beautiful, low-maintenance garden.

Another benefit of growing plants in 4 to 5 inches of gravel? A significant reduction in the number of weeds! Since no soil exists in the top 4 to 5 inches of the bed, weeds don’t have a chance to root in. Maintaining this “sterile” environment is a matter of simply making sure old plant material is removed from the bed each spring, and that no organic material is left on the beds (which could potentially break down to humus).

Not only will these beds help to bring added color to the parking lots as they fill in, but they will also introduce new taxa to the Garden. Although these beds will be full of color in time, we will need patience in the short-term. The beds will take some time to establish, with only a few flowers this year, a bigger display next year, and with the beds hitting maturity in 2019. It is my hope that this patience will give way to something beautiful for years to come.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Using peonies as a cut flower for floral design is easy, with a few tricks to preserve the health of your plants and flowers.

Peonies are the queen of the garden during their blooming season. From late spring through early summer, there is a beautiful abundance of color and shapes blooming, depending on the variety. Finding a variety that is also fragrant adds to the reward of growing this exquisite flower.

Storing peony stems allows you to use early and mid-season blossoms together in an arrangement.

Storing peony stems allows you to use early and mid-season blossoms together in an arrangement.

Here are few tips to extend the bloom of cut peonies indoors.

When cutting flowers from your plants, be sure to leave at least two sets of leaves on the stem so that the plant can continue to thrive.

You can select flowers that are as open as you like, but for the best vase life, select buds that have just begun to open and feel similar to a marshmallow. 

Cut stems can be stored in the refrigerator for two to three weeks, butno fruit—such as apples—can be in the refrigerator with your peonies. The ethylene gas emitted by ripening fruit will cause petals to drop, and buds to wilt and fail to open. I store peony stems so that I can use early- and mid-season blossoms together in the same arrangement. (This is also a good safety net if you are hoping to use peonies for an event, but Mother Nature decided to allow the peonies to bloom early.)

I have success in storing blooms two ways. One is by placing cut stems in a clean vase of cool water in the refrigerator, making sure that low foliage is not in the water. This can be challenging because the height of the stems don’t always fit in the fridge very well. The other method is to cut the stems and place them lying down in a plastic bag with a dry paper towel to absorb moisture. Both methods require daily checks to replace the water in the vase or the paper towels. If any of the blossoms in the plastic bag grow moldy, the infected flowers should be discarded, and the remaining flowers placed in a clean plastic bag. If the buds droop, don’t worry—often they can be revived in a vase of warm water.

Got ants? Ants love the sweet nectar of peonies as they begin to open. I dunk the blossom end of the stem in cool, clean water for 30 seconds to rid the ants from the flower before bringing the flowers into the house.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Well, here we are with another titan arum in bloom at the Chicago Botanic Garden. (Java, the taller of our Titan Twins, began blooming at 8:28 p.m. on May 30.)

We never really considered the possibility that we might have two plants developing inflorescences at the same time. But it did not take too long to brainstorm some ideas on what we hope to learn from this rare possibility.

We have nicknamed these corpse flowers the Titan Twins because they grew from seed from the same parent plant.

The plants have been named Java and Sumatra, in recognition of two of the major islands in the nation of Indonesia. Amorphophallus titanum, the Latin name for the titan arum species, is native to the island of Sumatra.

The corms of the Titan Twins were almost identical in weight when they were measured several months ago; the young inflorescences emerged from the soil within 24 hours of each other, and until recently, they were within an inch of each other in height. On May 18, Java became—and remained—the taller of the two.

A school field trip visits the two titan arums on May 23, 2017.

A school field trip visits the two titan arums on May 23, 2017.

Java: height=79.75” and circumference 51.25”; Sumatra: height=69” and circumference of 54.75” at the moment

So what will we do to take advantage of possibly having two sibling plants coming into flower at the same time? We can’t cross-pollinate them, because this species has an incompatibility system that prevents successful fertilization between closely related individuals. Even if this weren’t the case, we want to maintain the highest levels of genetic diversity when producing offspring of this rare species—a conservation practice common among captive breeding programs of animals in zoos. (The Garden began collecting titan arums in 2003, as part of a worldwide conservation effort to preserve the species.) We do hope to pollinate one of the titan arums with pollen from an individual from another institution that has been stored “on ice” for just such an occasion. 

Having two plants blooming at nearly the same time allows us do an experiment to answer a question about what happens to the inflorescence just after pollination.

When Alice the Amorphophallus and Sprout bloomed at the Garden (Alice in September 2015 and Sprout in April 2016), we wondered if pollination of the female flowers influences how long the plant generates odor and heat. It is possible that when pollination takes place, it signals the plant to save energy and stop these energetically expensive processes. After all, pollination of the female flowers basically signals to the plant, “job well done.” Perhaps at that point, there’s no need to continue with the energy-intense display.

Dr. Pati Vitt checks out the pollination situation on our April 2016 bloom, Sprout.

Dr. Pati Vitt checks out the pollination situation on our April 2016 bloom, Sprout.

With two plants from the same parentage blooming at nearly the same time, we can do the experiment that could answer this question. We will not pollinate Java, the first plant that came into bloom, and then pollinate Sumatra, assuming it does open. We will record heat at regular intervals through use of a thermal camera and determine if the unpollinated inflorescence produces heat for a longer period than the pollinated one. Measuring odor production will be a bit more subjective—that will require sniff tests, and an abundant supply of fresh noses. Hopefully we will find some volunteers!

Check the video feed on the website, and plan your visit to see the titans in bloom today!

Patrick Herendeen and Pati Vitt


©2017 Chicago Botanic Garden and my.chicagobotanic.org

DIY Living Plant Wall

Kathy J. —  May 15, 2017 — 1 Comment

This year, the Living Wall in the Grunsfeld Children’s Growing Garden needed to be replanted. The metal cells that hold the plants to the wall were removed and taken to the Garden’s greenhouse nursery to grow new plants before placement outside for the summer.

This left us with four empty walls at the entrance to the Growing Garden. So we decided to get creative. We made an “alternative” living wall. 

PHOTO: sixteen cone-shaped pockets containing small plants are displayed on the brown walls.

The south-facing wall is now covered with burlap pocket planters containing alyssum, lettuce seedings, grass, and coriander.

Our carpenters covered foam boards with brown burlap and installed these panels on the living wall frame where the plant cells had been removed. Students from the Garden’s Nature Preschool planted seeds and transplanted seedlings into small pots. We placed the plants into colored burlap planters and pinned them to the foam walls, and voila! We have a vertical garden again.

You can do this at home. Making planting pockets is simple and fun.

  1. Plant seeds or transplant small plants and let them sprout. We used biodegradable Fertilpots, but you could also start seeds in egg cartons, newspaper pots, or plastic pots.

2. Cut the burlap into squares that are twice as long and wide as the pots.

PHOTO: The picture shows the size of the burlap square next to the pot that was used.

Our Fertilpots were 4″ tall, so I cut the fabric roughly into 8″-x-8″ squares. This does not need to be exact.

3. Fold the square in half diagonally and sew a seam along the side. You can use a heavy duty needle with a sewing machine or do this by hand with a darning needle. It might be possible to use a hot glue gun to make the seam, but I did not try this.

PHOTO: This shows what the burlap looks like after it is sewed in half.

I used a sewing machine because I made more than 100 of these. They could be sewn by hand.

4. Turn the triangle inside out to form the pocket. Slip the planted pot into the pocket and get ready to hang it on a wall.

PHOTO: This shows the pocket with a pot inside.

The seam side of the pocket is the back, and the pointed front top can either be folded down or cut off.

5. To hang on the wall, pinch the extra fabric so the burlap fits snugly around the pot. Fold down the point in front or cut it off—your choice. Push a long pin through the pot and the fabric and pin the pocket to the wall. (I had pins used by our horticulturists to propagate cuttings; you could use T-pins or other pins with large heads.) You could also lace a ribbon around the top of the pocket and cinch the fabric, then hang the planter by the ribbon.

PHOTO: The picture shows a hand holding the fabric to make the pocket fit around the pot.

Gathering the extra fabric will help hold the pot better, and it will look neater on the wall.

Students in our Nature Preschool enjoyed helping to grow the plants and pin them to the Living Wall. Each child wanted to place his or her planter next to a friend’s planter so they could grow close together.

wall KJ with girl

Just for fun, we experimented with some other kinds of planters, including plastic bottles and shoes.

PHOTO: a 2 liter plastic bottle turned sideways and filled with soil and oregano plants is pinned to the wall.

If you want to try growing a plant in a 2-liter bottle, cut a rectangular opening in the side of the bottle, poke six to eight holes on the opposite side for drainage, fill with soil, plant, and hang it up.

The preschoolers are fascinated by the soda bottle planter. They like to look in the round opening on the side. The toddler shoe makes everyone smile. We may add more surprising planters over the next few weeks, just to keep it interesting.

PHOTO: a toddler shoe with alyssum growing in it is laced with twine and hanging on the wall,

An old shoe can become a whimsical planter that sparks imagination.

If you decide to try something like this at home, be advised that the small pots need to be watered frequently (ours need watering daily) because they tend to dry out faster than larger containers. It’s a good project for young children because they will get to do a lot of watering without harming the plants.

Our “alternative living wall” is only temporary. Stop by the Grunsfeld Children’s Growing Garden between now and June 12 to see how it’s growing. After that, the real living wall will be installed for the rest of the year.


©2017 Chicago Botanic Garden and my.chicagobotanic.org

Like you, the staff at the Chicago Botanic Garden has been tracking the recent rains. We know many of you are anxious to get planting done—it is spring, right? But we encourage caution and patience.

If it squishes, wait. Working with wet soil and turf damages it.

If it squishes, wait. Working with wet soil and turf damages it.

Here are tips to help gardeners navigate Chicago’s spring:

  1. Wait until the soil dries out to get back in your garden. If the soil can form a sticky ball when you squeeze a handful, it is still too wet for planting. Soil will take longer to dry after periods of cool weather. Sandy soils can be worked much sooner after a rain event. Clay soil holds more moisture and requires a longer waiting time.
  2. Avoid excessive walking in garden beds and on lawns. It can compact and damage your soil.
  3. Soil is ready for planting when it crumbles in your hand. Working the soil when it is too wet can increase compaction and break down the structure of the soil, leaving you with hard crusts or clumps when it dries out.
  4. Don’t mow a lawn that is excessively wet. A lawn is too wet when you see standing water, or water comes up from the ground as you step on the lawn. In these conditions, the mower tires will leave muddy tracks that will damage your lawn.
  5. Now is the time to get in some really satisfying weeding!

    Now is the time to get in some really satisfying weeding!

    Do pull weeds once your soil has dried a bit. Weeds are more easily pulled when the ground is moist (but not wet). Work from the edges of the beds to pull weeds without compacting soil or damaging other plantings.
  6. Mulch beds once the soil has dried out. Be sure the beds are sufficiently dry.
  7. Drainage issues? If you can, collect water that has pooled. In order to correct a drainage problem, you will first have to move the excess surface water that is pooling in low areas. Then you can consider the different options to improve drainage, taking into account soil type and natural changes in grade.

tomatoes on the vineThe Garden recommends waiting to plant warm-season flowering annuals, vines, herbs, and vegetables until after the Chicago area’s average last frost date of May 15. Cautious gardeners often wait until Memorial Day before setting out cold-sensitive plants such as tomatoes, peppers, eggplants, and squash.


©2017 Chicago Botanic Garden and my.chicagobotanic.org