A Gardening Journal
Today in the Garden of a Lifetime: Fall Foliage of Climbing Milkvine
- Published: October 11 2016
We can only hope that our gardens are, on occasion, merely pleasing. That in itself is a victory. After that bar has been cleared, being beautiful and even transcendent is just a matter of degree, the reward of years of effort and expense. But still: Beautiful is only the intensification of pleasing. Ho hum.
Today, the milkvine in this picture brought what mere time, effort, and money could not: joyful surprise. To my knowledge, this species' Fall foliage color isn't commented upon. Heck, even I didn't include it in the lengthy profile of 2012—and hadn't discovered it all the years since. Until today, when early morning obligations extended into mid-day, delaying the first-of-the-day "What's happening in the garden?" stroll nearly until dusk.
The visit was more to reassure that the gardens' plants were fine—especially the many score of conservatory specimens still not brought into shelter despite the increasing risk of frost. Five minutes, then back inside to work.
But then I spotted this Matelea obliqua, whose mid-green Summer foliage had turned into a serpentine cascade of gold.
This native vine sends up fresh stems from the ground each season; this year some were long enough to ascend a low branch of the contorted beech. In the picture below, you can see that the beech foliage—much more leathery and durable—has yet to display any colorful effects of the increasing overnight chill.
The milkvine foliage is racing ahead to its Fall peak. You can see how much brighter its leaves are than either those of the gold-leaved winterhazel at the center right, or the gold-needled plum yew at the bottom left. The leaves of Corylopsis spicata 'Aurea' have yet to adopt Fall colors; their faint chartreuse is all that remains of the more vivid shade they displayed Spring to mid-Summer. Needles of Cephalotaxus harringtonia 'Korean Gold' emerge gold in Spring and Summer; they maintain that color through Winter, and modulate to green only in the following year.
The brightness of the yellow coloring of the leaves of Matelea obliqua could be related to the ephemeral nature of this species' above-ground growth. Not only is its foliage shed in the Fall; its stems are abandoned, as well. (The winterhazel sheds is foliage for the Winter but retains its stems; the plum yew retains foliage and stems both.) With chlorophyll-sustaining water soon cut off not just from the leaves but from their stems, the result could be a more thorough and, therefore, more vivid display of the remaining pigments (yellow in this case) than if just the leaves themselves were shed.
In the picture below, you can see that the portions of the leaf blade between the veins have already changed to yellow. The remaining moisture in the leaves is in those veins, and as it, too, is transpired, presumably those remaining areas will also turn yellow. I'll monitor the leaves in hopes of confirming this transition.
This species hardiness into Zone 6 may well be made possible by this full retreat below ground before any seriously cold weather arrives. Whatever the factors that produce both its hardiness and the Fall coloring, milkvine's Fall display is unstinting. In Spring and Summer, the vine is a subtle delicacy. Its very cool flowers are small enough that they usually need to be pointed out to garden visitors, while its few gently twining stems bear heart-shaped leaves that aren't really worth noticing unless you already know that, yup, this is the obscure native climbing milkweed, and want to pat yourself on the back for being such a plant geek that you knew to look out for it.
But for a week or two in Fall, this oddly reticent vine struts to center stage and, if any vine could, channels Ethel Merman. Truly, you can see its Fall foliage even from cheap seats (and high ladders) far across the garden.
Sing it, sister!
Here's how to grow Matelea obliqua, as well as pictures of its sophisticated starry flowers and mid-green Summer foliage.