How Do You Make Caterpillars, a Ladybug, and a Frog Bloom?

Posted in Gardens and Collections on April 21 2009, by Plant Talk

Katie Bronson is Gardener in the Everett Children’s Adventure Garden.

Horticulture staff on the Outdoor Gardens crew welcome spring in the Everett Children’s Adventure Garden by dressing the five animal topiaries—three caterpillars, a ladybug, and a frog—in colorful Viola coats. The topiaries delight visitors year round but seem to bring a special joy after a long winter and before the spring bulb and flowering tree season gets into full swing.

What exactly does it take to make a caterpillar bloom? Many hands, many plants, and a lot of time.

Although it takes about seven days to plant all five forms, the process starts months in advance. During the summer, we drew designs and selected the varieties of violas to use. The staff at the Nolen Greenhouses for Living Collections started growing the plants in late fall to be in flower and ready to plant by mid-March. Turning a drawn design into a planting involves a little bit of math and a lot of eyeballing. As we do the installation, we keep track of how many plants of each variety we have and how many we have used to ensure there are enough to complete the design as planned.

Before planting, the topiaries look like soil-filled wire cages in the shape of an animal. Planting in the steel structure is pretty much like planting in the ground except that sometimes we are standing on ladders and sometimes we have to lie on our backs to plant. To achieve an instant effect, the plants are planted much closer together than they would be in the ground.

Soil knives are our tool of choice, because they are flat and narrow and cause less soil to fall out of the structure as we dig. We don’t usually need to replace the soil that falls out, because the new plants take up that space—as the plants grow, they root into the structure. Many plants are planted practically upside down in the structure. When gravity wants to pull our plants out of place, we use landscape staples to pin the root balls.

After planting is completed, areas that have lost soil are stuffed with damp sphagnum moss to keep the roots from drying out. Irrigation systems are installed inside each structure, but we water by hand right after planting and then usually on a schedule of once or twice a week to supplement the daily irrigation.

Can you guess how many violas it takes to make a caterpillar bloom? To find out the answer…

Each caterpillar comprises a different number: one needs 585 violas, another 625, and the third 670!