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ANOTHER ODE TO
TRUMPET CREEPERS

Sometime 'way back in the last century--it must have been the fall of 1982--gentle autumn breezes swept up a winged seed and carried it to the property that had just become Hilton Pond Center. The seed landed just outside a large kitchen window of our old farmhouse and fell into a crack or crevice that protected it from being eaten, and it undoubtedly spent the winter getting chilled to just the right temperature. When spring came and the earth warmed, the seed absorbed water, swelled, and germinated, eventually sending out a hypocotyl that produced roots and an epicotyl that gave rise to a tiny stem. Something must have been just right in the soil, for that first stem grew rapidly and branched and bore foliage that, in turn, carried out photosynthesis so that the plant flourished throughout summer and fall--only to become dormant as the cold days of winter returned.

All text & photos © Hilton Pond Center

Next spring, however, the young plant--which had been a mere seed two years before--awoke from winter slumber and was off to the races, elongating its roots and extending its vine-like stems across the substrate, fueled by sunlight converted to sugar by chlorophyll in its green compound leaves. Protected by the Center's philosophy of "don't-cut-it-unless-you-have-to," the plant grew by leaps and bounds and by its second autumn had reached a foot or so in height and covered a circle about a yard in diameter. As winter approached once more, the plant again dropped its leaves and settled in for the cold months, then as spring returned it repeated the cycle of growth. This time however, the plant made more than stems and leaves; this time, it produced a few of those familiar big blooms of Trumpet Creeper, Campsis radicans--a plant we cherish above all others at Hilton Pond Center.

Ah, Trumpet Creeper, whose showy orange blossoms herald both the end of May and the hatching dates of our first nestling Ruby-throated Hummingbirds in the Carolina piedmont. This plant, despised by some gardeners as a weed, is just what is needed by mother hummers, whose long, thin bills mesh perfectly with long, narrow flowers of the Trumpet Creeper--certainly one of the most prolific nectar producers in eastern North America. We've often thought that if all the Trumpet Creepers in the U.S. were to disappear suddenly, our ruby-throats would have a very tough time--so critical is this plant as a food source for adult and nestling hummers.

Just as Trumpet Creeper is of great use to hummingbirds, so do hummers have significant value for the Trumpet Creeper when it wants to pass on its genes. The creeper has rather large reproductive structures--five twisted, pollen-bearing stamens (above) and a very elongated pistil that is left behind when a withered flower tube drops off (below).

The pistil and stamens are located asymmetrically along the top rim of the flower tube, and the Trumpet Creeper's nectar is produced deep within the tube. When a hummingbird visits and plunges its bill through the tube opening in search of nectar, it can't help but bang its forehead against the stamens, thereby picking up a dusting of sticky pollen. Sometimes a hummingbird is so intent on collecting nectar that it visits a succession of Trumpet Creeper flowers--so many that the bird's head looks as if it has been marked with whitish-yellow paint (see photo above).

Trumpet Creepers are happy to have these industrious nectar-lapping visitors, of course, since the hummers play a role in transferring pollen from one flower to the next. This week, as we were taking photos, we discovered something that likely facilitates pollen transfer: The pistil is not only long, but its tip is paddle-like--i.e., flattened top to bottom (left, and photo just above). This assures that the maximum surface area of a pistil touches the hummingbird's forehead, and that the pistil receives an optimum amount of pollen. We also noticed that a day after the flower tube falls away, the pistil's tip splits vertically, possibly a sign that a pollen tube is growing down the pistil toward the ovary.

Even though the loss of all the world's Trumpet Creepers likely would not bode well for Ruby-throated Hummingbirds, we suspect the elimination of ruby-throats might not have as great an impact on the well-being of Trumpet Creepers. That's because the big, tubular blossom of the creeper is attractive to a wide variety of pollinators. In fact, on a sunny day this week at Hilton Pond Center, we saw an amazing diversity of insects--all visiting blossoms among our huge patch of Trumpet Creeper surrounding the spot where that very first seed germinated more than 20 years ago. Today the creeper colony contains a dozen or more plants like the ten-foot-tall one pictured above, and several vines climb adjoining trees too high for us to see--much less identify--all the miniscule insects visiting the creepers' flowers.

Closer to ground level, the most obvious six-legged pollinators were bumblebees so large that when they entered the flower tube in search of nectar, they--like hummingbirds--brushed against Trumpet Creeper stamens and picked up pollen that later would be deposited on another flower's flattened pistil. But some bumblebees "cheat" when seeking nectar, probing through the joint at the flower's base and avoiding its pistil and stamens. (We've seen young hummingbirds do the same thing, particularly as the flower ages and is ready to fall to the ground.) Worse yet, Carpenter Bees sometimes bypass the creeper's reproductive structures AND damage the flower by cutting a half-inch hole holethrough which they enter before the blossom even opens or the pollen is ready (left). These nectar-robbers still qualify as nectarivores, but they're certainly NOT pollinators, and might even be thought of as predators on the Trumpet Creeper's flowers.

Despite the danger of attracting insects that don't pollinate, Trumpet Creeper actually goes one step further in advertising the pool of plentiful nectar in the far recesses of its flowers. Along the floor of each blossom are dark thin stripes (below) that undoubtedly point large bees toward a sweet reward at the end of the floral tube, a goal they can't reach without brushing against the reproductive structures. We liken these "bee guides" to roadside billboards that announce a long-awaited restaurant awaits just a little further down the highway.

With camera ready, we stood this week in the middle of our expansive Trumpet Creeper patch and marveled at the non-stop parade of insect visitors. In less than a hour's time, several species of tiny, solitary bees flew in and entered the collective inflorescence, but most didn't even bother to go for nectar. These quarter-inch bees were interested, it seems, only in the Trumpet Creeper's pollen, which--judging from the yellow-white deposits on some bees' legs (left)--they must have collected as food for larvae in some nearby nest hole. On just one creeper flower we observed jet-black bees and several metallic-looking ones that were blue or green or gold (below)--and even a fast-moving Hoverfly that mimicked a bee with its banded yellow-and-black abdomen.

We regret we know too little about fly and bee taxonomy to identify any of the species we saw. For now we simply offer our photos as evidence that the orange tubular flowers on which these insects feed are indeed important to pollinators, and worthy of "Another Ode to Trumpet Creepers" at Hilton Pond Center.