Plant Flowering Seasons Vs. Bee Seasons
knows that certain flowers bloom at certain times of the year. For
example, most Ceanothus species flower in the spring and
native sunflowers and Cosmos bloom during the summer months.
These are very predictable seasonal phenomena.
The same type of seasonal activity is also true
for bees – some can be expected in spring, others in summer,
and still others in early fall. The seasonal patterns of bees and
flowers are often tightly connected – bees make sure to wake
up from winter hibernation right on time to collect nectar and pollen
from their favorite plants. Likewise, plants schedule their blooms
to coincide with the emergence of the best pollinators to ensure
their pollination and reproduction. This seasonal scheduling is
especially clear for many native
bees and flowers, who have developed special relationships over
long periods of evolution.
example, during spring, two groups of bees are commonly found visiting
several spring ornamentals such as California poppies. These are
megachilid bees of the genus Osmia (often metallic
green or blue depending on the species) and andrenid bees
of the genus Andrena (all black or a combo of buff and black).
These two genera usually cannot be found after the first of July.
Bumble bees of the genus Bombus are also present primarily
during spring visiting a wide variety of ornamental plants.
the summer, several other megachilid species (non-Osmia)
can be observed visiting urban gardens. A few of these species are
the size of honey bees and visit several types of ornamental plants.
All of these summer “megs” have black and white banded
abdomens in contrast to the shiny green and blue Osmia of
and females of the anthophorid genus Melissodes (see photos
at right) are common during the summer and early fall. Female Melissodes
(left photo) are roundish, stocky, hairy and are regular visitors
to plants such as Cosmos, Gaillardia, and sunflowers
where they get both pollen and nectar. In contrast to females,
males (right photo) have longer, wirey bodies, and have very long
antennae. Males also visit Cosmos
and sunflowers, but for nectar only.
texana of the family Halictidae is another summer-early
fall bee. It is occasional in the San Francisco Bay Area, but the
striking color differences between males and females makes them
worthwhile to search for in your garden (see photos above). Females
(left photo) have a bright metallic green thorax and abdomen,
whereas males (right photo) have a metallic green thorax and
a striped yellow and black abdomen. A.
texana can be observed on Cosmos, Grindelia
(Gum Weed), and Bidens ferulifolia.
In contrast to the highly seasonal native California
bee species, the exotic honey bees can be found commonly year round
on numerous flowering plants. Like the native California bees, honey
bees also have their preferred flowers.
Recognizing seasonal differences in flowering and
periods of bee activity can be useful for planning a garden that
can cater to spring, summer, and fall bees.