Goldenrod and Asters

Summer’s last refrain is sung by goldenrod and asters. Like one last hurrah, goldenrod and asters delight the late-season pollinators and please the eye with their blaze of purple and gold.

There are a few species of goldenrod native to the northeast of the continent, but one of the most common is Canada Goldenrod (Solidago canadensis). It’s bright, showy flowers bloom in clusters along the ends of arching branches.

Goldenrod is often blamed for causing hay fever, but its pollen is too heavy to be wind-borne. Instead, it relies on insects such as the bee in the opening photo to carry its pollen from flower to flower. Hayfever is caused by plants that are wind-pollinated, such as ragweed. As they don’t need to attract insects, flowers on wind-pollinated plants are often inconspicuous.

Patches of goldenrod can be very old. If undisturbed, a goldenrod colony can reach 100 years of age and more. That’s because goldenrod sends out long, creeping rhizomes from the base of its stem. A circle of new plants may spring up around a pioneer seedling. Rhizome production begins after the first year of seedling development. Shoots emerge from rhizomes in the spring, around mid-April.

After the yellow flowers are finished, goldenrod takes on a wooly appearance as the dried seed heads take over.

Goldenrod is popular with insects. One insect commonly associated with goldenrod is the Pennsylvania Leatherwing (Chauliognathus pennsylvanicus), which you can see here. An insect that uses goldenrod as its winter home is the goldenrod gall fly (Eurosta solidaginis), a member of the fruit fly family, along with the well-known pest, the Mediteranean fruit fly. [The flies that buzz around fruit on your counter are actually vinegar flies, or Drosophila.] The goldenrod gall fly overwinters as a larva inside a round gall on the goldenrod stem. For more about galls, visit this post from March. The galls represent both next year’s fly population in the making, and a winter food supply for birds.

Goldenrod is a member of the aster family. There are many species of asters, but one of the best known is the New England aster (Aster novae-angliae). Its compound flower head features yellow central disk florets surrounded by purple-blue ray florets.

The genus name Aster means star. It is certainly a star in the late-summer meadow. New England aster can be differentiated from the similar fringed aster (Aster ciliolatus) by its leaves, which are long and narrow, while those of the fringed aster are heart-shaped.

Native plants are always a good choice for the home garden and there are a number of native varieties and hybrids of both solidago and asters available. Solidago “Little Lemon” is a short hybrid, just 12 inches tall, appropriate for the front of the garden. Solidago rugosa “Fireworks” reaches about 40 inches and features an upright, bushy habit and large heads of golden flowers. Some of the cultivars of New England aster include “Purple Dome” and “September Ruby“.

Below, a Cabbage White (Pieris rapae) butterfly visits a New England aster.

Read Full Post »

Bibliophilia Monday: Kaufman Field Guide to Insects

Kaufman Field Guide to Insects of North America by Eric R. Eaton & Kenn Kaufman. Houghton Mifflin, 2007.

My interest in insects is modest. Like many people, I find mammals easier to appreciate! However, insects are so plentiful, it is impossible not to come across them … pretty much everywhere! Insects are vital members of ecosystems. The incredible diversity of insect species is amazing. Also amazing is the ingenuity with which evolution has equipped so many different species to so many specialized niches. The best guide I’ve found for identifying the insects I come across is the Kaufman guide by Eric Eaton. The introduction provides good background information on the classification of insects, their anatomy, reproduction and development, and more. The guide is well-illustrated with more than 2,300 images and the organization of the guide makes it simple to locate the insect you are looking for. Below are a few insects that I was able to identify with the guide.

Pennsylvania Leatherwing

Soldier beetles (family Cantharidae) are also known as leatherwings. These valuable pollinators are attracted to flowers, and can be abundant during the day on their preferred plant. The Pennsylvania Leatherwing (Chauliognathus pennsylvanicus) is commonly found on goldenrod and thoroughwort in the east in autumn. The photo above, showing them on goldenrod, was taken last fall.

Squash bugs belong to the Coreidae family, which includes leaf-footed and broad-headed bugs. They’re pests of gourds, pumpkins and other types of squash. They feed on foliage using piercing and sucking mouthparts. Later in the season, they may also feed on the squash itself. I found these squash bugs (Anasa tristis) on a squash last fall. Although there were quite a few bugs on the plant, they didn’t damage this squash.

I visited the Central Experimental Farm Garden, where Felicitas Svedja once produced her hybrid roses, in Ottawa a few weeks ago. A few of the roses in the display garden were heavily infested with these colourful beetles. When I got home, I looked them up in my Kaufman Guide. They’re Japanese beetles (Popillia japonica). They’re native to Japan and northern China and were introduced to New Jersey in 1916 on nursery stock. They are now found throught the eastern U.S. and southeastern Canada. The adults feed in groups on a wide range of plants, but they are obviously fond of roses, skeletonizing the leaves.

Read Full Post »