Two Powerhouse Keystone Species: Solidagos and Quercus
I'm pretty excited about Shropshire and Tallamy's concept of Keystone Plants (from Doug Tallamy's latest book, Nature's Best Hope).
I really like the idea that even if my yard is small, my budget is not generous, or time for maintenance is limited, that I can still make a difference. I enjoy the idea that I can get maximum bang for my buck by strategically selecting some plants that science has found to provide more value.
Keystone species bring more of the sun's energy into the ecosystem by
being excellent host plants (particularly for caterpillars, which in turn feed many other species such as birds)
supporting bees, which are needed to pollinate not just our human food, but much of the rest of the blooming ecosystem
Tallamy's book is written for a national audience, so I thought I'd get more specific and share several of our Mid-Atlantic keystone plants with you. The best way to select the right plants is by knowing a little about them: Where they prefer to grow, how tall they are, and what they will accomplish in a landscape, for example.
The Solidago Family. Native bees need nectar and pollen, but also nesting sites. The goldenrod family provides all 3 of these in one rugged, widely adaptable, late-blooming package. They meet the needs of many specialist bees (I'll write more about specialists vs. generalists in another article). For all these reasons, goldenrods are powerful keystone plants.
The only problem with most goldenrods is that they can quickly overwhelm a garden, leaving you with little diversity. Diversity is important because we need early, mid-season, and late sources of nectar. It's also important because we humans value things like beauty, variety, and, ahem, tidiness...
I'd like you to meet Solidago caesia , Wreath goldenrod—a more delicate-looking, woodland goldenrod that is clump-forming, non-aggressive in the garden and tolerates nearly every kind of situation except wet: happy in sun or shade, sand or clay.
Wreath goldenrod grows 18-24" in most cases, occasionally to 3' if there is a lot of competition. Deer or rabbits may nibble but will likely not completely consume it. And it is not too hard to find at native plant retailers.
Wreath goldenrod is host plant for well over 115 different species of caterpillars, and supports specialist and generalist bees with pollen and nectar. For these reasons, and because it is so much more shade tolerant than many other goldenrods, I use it often in woodland-style shade gardens. It combines beautifully with ferns and Wild columbine.
The Quercus Family. For caterpillar support, trees have more leaves than a shrub or perennial. If you have room for just one tree, you really can't beat the Oak family. Red oak, white oak, black oak, pinoak, willow oak... According to Tallamy,
"Oaks are ranked either #1 or #2 in their support of the food web in 84% of all US counties in which they occur."
In fact, oaks in our mid-Atlantic region support 557 caterpillar species! And yet they do it with ease—when I worked as an IPM scout, we would find caterpillars on oaks but we never put them in our report as needing attention (except for gypsy moth caterpillars), because even with the nibbled leaves, the trees were completely healthy.
If you have limited space or tough circumstances for growing a tree, such as poor-draining soil, you might like to get acquainted with Quercus bicolor, Swamp White Oak—a smaller size oak that can adapt to wet or compacted soil, is drought tolerant once established, and has a nice overall, slightly smaller form—only 50-60 feet tall compared to the 100' that Quercus alba can achieve.
Like many plants that can grow in saturated soil, it is also adapted to dry, compacted soil, because the adaptation is actually to the lack of oxygen in the soil, and both poor drainage and compaction are low-oxygen situations.
Well, hmmm, that was only two species (!) and I wanted to write about many more...perennial sunflowers, asters, and willows, at least! Let me know if you want longer newsletters, otherwise I think I will take a break here and we can all get back outside to the garden!
Stay healthy!
Chris
P.S. I'm offering a new service for those who are interested: SMARTPHONE CONSULTING. Yes, it's exactly what it sounds like! We did one Friday and it was really fun! More info on SMARTPHONE CONSULT VISIT here.