Hummingbird moth on moonflower
Many people enjoy their gardens during the daylight hours and head indoors as the sun starts to set. But if you install a moon-moth garden, you’ll find yourself anticipating the approach of late afternoon and early evening when you’ll be able to watch the flowers open followed by the night insect visitors (mostly moths).
Jimson weed flower
Blossoms of the night-blooming or angled loofah
Did you know that “vespertine” refers to plants with flowers that open at night? In biology, we use the word “niche” to mean the function that an organism performs in the community, and butterflies, bees and hummingbirds fill the niche of pollinating during the daylight hours while moths take over that niche when the sun goes down. All three of these insects (bees, butterflies and moths) and hummingbirds are attracted to flowers not to pollinate them, but to gather nectar for their own food directly or, in the case of the bees, to be made into honey. The transfer of pollen from one flower to another (pollination) is a secondary spin-off of nectar gathering. With darkness, moths have a more difficult time finding their nectar sources, so those night-pollinated flowers are usually light colored – white, light yellow, etc. – and they often have a strong fragrance. There are a number of moth species that fill the niche of night pollinators but the most spectacular and noticeable are the generic group of hummingbird moths. Some of these are technically called sphinx moths or hawk moths but I call them all hummingbird moths because they look, fly and hover like hummingbirds. They also have a long proboscis similar to the long beak of a hummingbird. My first exposure to hummingbird moths was as a kid – I noticed what I called hummingbirds visiting the four o’clock (Mirabilis jalapa) flowers near our front porch; it was not until many years later when I learned about hummingbird moths that I realized those hummingbirds that I thought I saw as a kid were actually hummingbird moths.
Over the past few years, I have spent many evenings outside around my moon-moth garden and almost always I am rewarded with a visit by one or more hummingbird moths. I have also witnessed my cat trying to catch one!
As mentioned earlier, four o’clocks are good hummingbird moth-attracting flowers, no matter what their color. These flowers also seem to be the first to open as the daylight hours disappear, and have the strongest odor of my moon-moth plants.
Allen Acres Moon-Moth Garden with desert thorn apple (large white flowers) in foreground, jimson weed (right rear) and night-blooming loofah on trellis in background.
Desert thorn apple or devil’s trumpet (Datura metel) is another good plant. It has very large, pure white flowers that the hummingbird moths seem to really like. Perhaps there is more nectar in large flowers. The only drawback to this plant is that it cannot sustain the production of these flowers for a long period of time. The related jimson weed, Datura stramonium, is also an attractant. The flowers are smaller but the moths will still visit these flowers as well. I have observed that the moths seem to shy away from the dark-flowered varieties of daturas. Other species of datura will also work as long as the flowers are white or very light colored.
I like to add moth-attracting flowers through the use of vines, and the best for that is moonflower (Ipomoea alba). Another vine that will attract hummingbird moths is the night-blooming or angled loofah (Luffa acutangula); it is also called ridged loofah, vegetable gourd, silk squash and vine okra. The flowers are yellow and open at night and the fruit is long and narrow and can be eaten when young. There is another species of loofah, Luffa aegyptiaca, that also has yellow flowers but they open in the morning; the fruit is short and develops the fibers early, and thus is not edible but better suited as a “sponge.”
Allen Acres’ quarter moon-shaped moon-moth garden
Hummingbird moth and its long proboscis in a four o’clock bloom
Four o’clocks, datura, moonflower and loofah are the four varieties that I have used in my moon-moth garden, but I have also observed hummingbird moths at a white spider flower (Cleome hasslerana). An interesting vine is the largeroot morning glory (Ipomoea macrorhiza), a lavender night-opening vine that is native to south Florida. This is a great hummingbird moth nectar plant but it is very picky in soil requirements; it only grows in very sandy soils.
To enhance my moon-moth garden, I have created one planting area in the shape of a quarter moon and placed the daturas and four o’clocks in this bed. Nearby and just to the north and west of the quarter moon-shaped bed, I placed another L-shaped bed with a trellis. In this bed, I plant moonflowers and the ridged loofah. These two vines bloom later than the daturas so I have a staggered flowering period for the moths. I created other beds nearby and populate them with more daturas, four o’clocks and white spider flowers. I also have larger plants of other moth-attracting plants, including gardenia or cape jasmine (Gardenia jasminoides), almond verbena (Aloysia virgata) and night-blooming jasmine (Cestrum nocturnum). I see lots of hummingbird moths visiting porterweed (Stachytarpheta urticifolia) just before daylight, when these flowers open, getting their share of the nectar before the bees and butterflies visit it during the daylight hours.
So plant a moon-moth garden. You’ll extend your enjoyment of your outside spaces and help provide nectar to not just the day insects, but the nighttime ones as well.
A version of this article appeared in a September 2011 edition of the State-by-State Gardening enewsletter.
Photography courtesy of Dr. Charles Allen.