Ornamental plants have a place in the CT garden

WILTON - A new study shows there are numerous ornamental plants — some of which are native and some not native to Connecticut — that are frequented by honey bees.

Scientists from the Connecticut Agricultural Experiment Station, in collaboration with researchers from the Center for Pollinator Research at Penn State University, York University in Toronto, Canada, and the University of Maine, recently measured pollen collected by honey bees in three commercial ornamental nurseries.

The study showed honey bees, which are not native to Connecticut, collected pollen from a very diverse mixture of plants and included one surprise — the water lily. Of no surprise were some of the common ornamentals and other plants often considered weeds: clover, plantain and ragweed.

The ornamentals included native and non-native roses — although hybrid tea roses have little appeal to bees and multiflora rose is a noxious invasive species.

Also figuring in frequently were goldenrod, which is native although some types are common and some are ornamental, and spirea, most of which is not native. Viburnum, of which there are hundreds of species, also figured prominently in the study.

Both native and non-native hydrangeas were also favored by bees although Kimberly Stoner, senior author of the study from the Experiment Station’s Department of Entomology, said in the case of hydrangeas humans and bees are attracted to different parts of the plant.

“Hydrangea have sterile flowers,” she said, but there are “functional flowers” that the bees frequent.

“Bees don’t look at the same things we do,” she added.

“Perhaps the lesson to be learned is that honeybees have a much wider range of flowers they enjoy than we humans do. They can benefit from the flowering ornamentals we plant and from our weeds, too.”

While honeybees feed on a wide variety of plants, native bees can also feed on some non-native species, she said.

There are about 350 types of bees native to Connecticut and of those, about 50 are specialists, favoring particular types of plants.

“There are a lot of species that are solitary,” she added, and some that have a short period of activity. They are not specialists in terms of plants but in the time of year — as short as six weeks — when they are active.

Stoner wanted to emphasize the importance of plants often considered weeds, including white clover, which often has many different types of bees on it and red clover, which is important for honeybees.

Stoner passed along a list of plants from a study on woody ornamentals for bee-friendly landscapes in the Ohio Valley region done by Bernadette M. Mach and Daniel A. Potter of the University of Kentucky. Many of these plants, she thought, would also grow here.

The woody ornamentals — both native and non-native — most favored by honeybees included:

 Cornelian cherry (Cornus mas).

 Higan cherry (Prunus subhirtella “autumnalis”).

 Foster’s holly (Ilex x attenuata)

 American yellowwood (Cladrastis kentukea).

 Common winterberry (Ilex verticillata).

 Linden (Tilia cordata, americana).

 Golden raintree (Koelreuteria reticulata).

 St. John’s wort (Hypericum frondosum).

 Bee bee tree (Tetradium danielii).

 Winged sumac (Rhus copallinum).

Along with American yellowwood, golden raintree, and St. John’s wort, the top woody ornamentals for bumblebees are:

 Red horsechestnut (aesclus x carnea).

 False indigo (Amorpha fruticosa).

 Buttonbush (Cephalanthus occidentalis).

 Sweetspire (Itea virginica).

 Clethra (Clethra alnifolia).

 Glossy abelia (Abelia x grandiflora).

 Seven-son flower (Heptacodium miconiodes).

To view Stoner’s paper, visit https://go.nature.com/391PEaO.

To view the University of Kentucky study, visit https://bit.ly/2UmrtzC.