Summer Phenology

Many phenology observers get excited about spring and fall phenological events but neglect summer. In spring, returning birds, emerging butterflies, leaves unfurling, and spring flowers blooming signal rebirth. Autumn gets lots of attention for autumn foliage here in Pennsylvania, and once again migration takes center stage. But summer is just more of the same -- everything is green, the birds are breeding (nothing new is arriving) and bees and butterflies are about visiting flowers but not much changes from day to day. Unless you look a bit more closely.

Mountain Laurel blooms at the beginning of June and gets lots of attention, but its cousin Rhododendron maximum (or Great Laurel) blooms at the beginning of July in hollows and hillsides, especially in cool, damp places.It has big, showy flower clusters and I saw the first blooms here on June 19 this year -- quite early in my recollection. The peak bloom was the last week of June and first week of July. Lots of bumblebees visited these blooms.
















Rhododendron/Great Laurel

Many other flowers also bloom at various times throughout the summer. Scarlet Beebalm (Monarda didyma) and Wild Bergamot (Monarda fistulosa) bloomed in mid- to late-June this year as well. Lots of native bees, butterflies, and Ruby-throated Hummingbirds have been visiting these flowers.


















Wild Bergamot (top) and Scarlet Beebalm

Speaking of bees and butterflies, some of these have fairly brief seasons as well. The diversity of insect probably peaks in mid-summer but the cast of characters changes. We are now beginning to see Monarch Butterflies (which will become abundant later in August), but their mimics, Viceroys are also out and about. You can tell the smaller Viceroy from the Monarch by the line across the rear wing of the Viceroy.














Monarch on Buttrerfly Milkweed (left); Viceroy (right)

Perhaps the most beneficial group of plants for attracting and helping insects is the milkweeds. We have Common (Asclepias syriaca), Butterfly, (A. tuberosa), Swamp ((A. incarnata), and Horsetail (A. verticillata) milkweeds in our habitat gardens and they bloom in June and July. The common and butterfly milkweeds bloomed first this year with the first blossoms opening on June 14. Swamp and horsetail have been blooming in the past week. Watch your milkweeds for lots of bees and butterflies, bugs and beetles. And also watch for beautiful Monarch butterfly caterpillars.














Common Milkweed and Bumblebee



There is lots more to record during the summer. Keep an eye on your gardens and backyards and let us know what you are seeing out there.