Invaders
Dare I Speak the Name?
As I was bicycling down the rail trail that runs past my back yard, I was almost bowled over by a most delectable aroma wafting from a most despised plants. 
The plants were autumn olives (Elaeagnus umbellata), shrubs whose fine qualities I’m reluctant to mention for fear of eliciting scorn from you knowledgable readers.
Yet, you’ve got to admit that the plant does have its assets, in addition to the sweet perfume of its flowers. Okay, here goes: The plant is decorative, with silvery leaves that are almost white on their undersides. And the masses of small fruits dress up the stems as they turn silver-flecked red (yellow, in some varieties) in late summer. 
Those fruits are very puckery until a little after they turn red, but then become quite delicious, and healthful.
(I included autumn olive in my book Uncommon Fruits for Every Garden, and also planted them — but that was before the plant became illegal here.)
Another asset of autumn olive is that it actually improves the soil, converting air-borne nitrogen, which plants can’t use, into soil-borne nitrogen for use by autumn olives and nearby plants.
This native of Asia, introduced into the U.S. almost 200 years ago, was promoted in the last century as a plant for wildlife and soil improvement. Decades ago I worked for the USDA in what was then known as the Soil Conservation Service (now the Natural Resource Conservation Service), an agency that not only promoted the plant but also developed varieties for extensive planting.
Autumn olive likes it here and has invaded fields throughout the northeast, the Pacific northwest, and even Hawaii. It’s an invasive plant. Don’t grow it! (But feel free to enjoy its aroma, its beauty, and its fruits.)
One of My Favorite “Invasives”
As autumn olive blossoms fade, the temporary vacuum in sweet-perfumed air will be filled by another plant, black locust (Robinia pseudoacacia). That aroma comes from the white blossoms that dangle in chains like wisteria blooms from this tree’s branches.
Like autumn olive, black locust has other assets in addition to those offered by its blossoms. It’s a leguminous plant, like peas and beans, so, with the help of bacteria residing in its roots, also puts air-borne nitrogen into a form utilizable by plants.
Black locust’s other assets refer to it when dead: The dense wood is very resistant to rot — much, much more so than cedar — and is very high in BTUs for burning. I converted all my garden’s fenceposts and arbors, which I had previously made from cedar and lasted only about 10 years, to locust.
I’m lucky enough to have a mini-forest of them growing along one edge of my property. I cut them when they are five or six inches in diameter, and in 10 or so years I have a new one to replace the cut one. It adds up.
Quick growth and the ability to resprout from stumps and grow in poor soil by “making” its own nitrogen makes black locust, like autumn olive, a plant not loved by everyone. Despite being native here in the U.S., black locust has been classified as a “native invasive.” The reason is that it was originally native to only two regions in the U.S., from which it has now spread far and wide.
Change Will Come
The classification of “native invasive” highlights the capricious legality and classification of invasive plants. Where is the boundary within which a plant becomes an accepted native? In the mountain that rises up just behind my valley setting, lowbush and highbush blueberry are thriving natives. But these plants would never turn up here on my land, except that I planted them. (And both thrive.)
Clove currant is another plant I grow, one that, in addition to bearing spicy fruits, is resistant to just about every threat Nature could throw at it: deer, insects diseases, cold, drought. And it’s a native plant, but native throughout the midwest, not here. Should I call it a “native?”
Black locust is such a useful tree that its spread was aided and abetted by humans. But it also would have spread, albeit more slowly, without our intervention. Even autumn olive, given enough time, might have hitch-hiked here in some way from Asia.
The Earth’s landscape is not static. Changes represent interactions of climate, vectors, chance, and time. Nostalgia may have us wishing for the view out the window to remain the same as it was when we were children, but that’s not Mother Nature’s way.
forsythia, mockorange, hydrangea, and any other informal shrub. This technique is known as rejuvenation pruning because, over time, the above ground portion of the shrub is annually rejuvenated. In the case of blueberry, the roots live unfettered year after year but the bush never sports stems more than 6 years old. A perennially youthful blueberry bush can go on like this, bearing well, for decades like this.
, rose-of-sharon, climbing roses, and flowering quince. These shrubs are among those that perform well year after year on the same old, and always growing older, stems. They also grow few or no suckers each year. The upshot is that thesis shrubs are the easiest to prune: Don’t.
An exhaust fan keeps temperatures from getting too high, which, with lows in the 30s, would wreak havoc with plant growth, at the very least causing lettuce, mustard, and arugula to go to seed and lose quality too soon.
Though not related to clover, oxalis (Oxalis deppei, sometimes called the shamrock plant) leaves are dead ringers for clover leaves — except that all oxalis leaves have four leaflets. And better still, oxalis can be grown as a houseplant, affording you “four-leaf” clovers for year-round proclamations of affection.
The plant spends summers outdoors in semi-shade near the north wall of my house, and winters indoors on a sunny windowsill. I water it perhaps twice a week, unless I forget.
This orchid is Dendrobium kingianum, which does go under the more user-friendly common name of pink rock orchid. I have also gotten this one to flower — but not every year.
And, like the tropical species, flowers are followed by egg-shaped fruits filled with air and seeds around which clings a delectable gelatinous coating. You know the flavor if you’ve ever tasted Hawaiian punch.
It’s peak of popularity was in the Middle Ages. And though popular, it was made fun of for it’s appearance; Chaucer called it the “open-arse” fruit.
Mostly I grow it for the novelty of an outdoor orange tree, for the sweetly fragrant blossoms, and for the decorative, green, swirling, recurved spiny stems.
Breeding, manipulation of their greenhouse environment, and plant growth regulators have transformed this sporadically blooming native of Mexico into a compact plant bursting into large blossoms for Christmas in foil wrapped pots.
Above 60°F, temperature steps in to play a role. At room temperatures, or thereabouts, a Christmas cactus needs about the same day length as does poinsettia, except that it might not need the weeks and weeks of short days before it decides to bloom. Then again, it might wait a few weeks, to throw in another wrinkle, depending on the variety of Christmas cactus.
This time of year, late fall going into winter, is when the plant is flowering and wants to be kept cool (preferably no higher than about 65°F.), moist (but not waterlogged), and in indirect light (which casts no more than a fuzzy shadow). Under these conditions, those butterflies can hover over the plant for weeks and weeks.
