JAPANESE & FLEA BEETLES, & LAISSEZ-FAIRE

I grabbed the dustbuster as I walked out to the garden this morning, hoping to inaugurate a new era in Japanese beetle control, who began their summer feeding early this month. The dustbuster was ineffective, the beetles passively dropping from any leaf as soon as the nozzle came within a few inches. Even beetles caught in flagrante delicto decoupled and dropped.

This year’s approach to Japanese beetle control will be laissez-faire. Spraying a chemical insecticide like Sevin is too disruptive to the ecosystem. Most organic insecticides, such as neem oil and pyrethrum, are either of limited effectiveness or require too frequent reapplication. And anyway, the beetles attack too many different kinds of plants to make spraying feasible; I’ve got over a dozen varieties of grapes, a half dozen varieties of roses, many varieties of filberts, and a dozen hardy kiwi vines scattered all over the place, and these are just a few of the beetles’ favorites in my garden.

In past years, I’ve put traps a couple of hundred feet apart at either end of the property. Each morning, the catch bags were stuffed full of beetles. But many of those trapped beetles would not have been on-site were it not for the allure (from sexual and feeding attractants) of the traps. The traps seem to work best when only a few Japanese beetles are in the area.

Japanese beetles can get sick from a fungus that attacks them while they spend late summer to late spring in the soil as white, C-shaped grubs. You can purchase the disease, milky spore disease, with which to infect them. Problem is that the disease is of limited effectiveness: Not enough grubs sicken and die and, even if effective, beetles emerging in summer can fly over from neighbors’ untreated yards.

I’ll probably do a little handpicking, knocking or dropping beetles in early morning, while they are still drowsy, into soapy water, from which an escape is too slippery. Hand to hand combat is satisfying and surely effective (for the ones killed, at least). Japanese beetles emit an aroma that attracts more beetles, so hand to hand combat is also intellectually satisfying in the knowledge that each beetle killed means fewer new ones attracted.

The laissez-faire approach has its merits. Plants tolerate a certain amount of defoliation, the remaining greenery ratcheting up photosynthesis to make up for leaf loss.  And if the plants can just hang on for a few weeks, the beetles then begin their exit anyway, their attention turning to laying of eggs in the ground to hatch into grubs for next year’s beetles. Well watered, lush lawns provide ideal conditions for egg laying and grub development; ‘nuff said.

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Flea beetles, which have peppered the eggplants’ leaves full of holes, will not be emulating Japanese beetles and exiting stage left anytime soon. If you grow eggplants, you have flea beetles, except for perhaps the first year or two in a new garden, before the pests have found your site. Other favorites on flea beetles’ menu are radishes, arugula, and turnips.

Flea beetles, in contrast to Japanese beetles, can be feasibly thwarted. A dustbuster, in this case, can be effective if used frequently enough. A thick mulch might interfere with their emergence from the soil. Fine mesh fabrics, -- “floating row covers” -- act as barriers although I like to be able to see my plants and the cover has to be removed during bloom to allow for pollination of eggplants.

Mostly, flea beetles are a concern with young seedlings, which can be killed, and for commercial growers, because customers don’t like to buy hole-y vegetables. 

Flea beetles hop away when disturbed and my favorite way to do them in is with the “flea beetle trolley” described on page 144 of Lawrence D. Hill’s Grow Your own Vegetables (Faber and Faber, 1971). Quoting Mr. Hill, “A wire in front disturbs the beetles which jump up and stick to the greaseband [flypaper or paper coated with Tangletrap would also work well]. The large wheels prevent sideways jumping.” The trolley works best on masses of leaves of small plants, such as radishes or arugula, rather than on widely spaced, larger plants with tiers of leaves.

Hot pepper may repel flea beetles. Research suggests that commercial “hot pepper wax” reduced flea beetle damage by about a half, so it may be worth a try.

I might take the laissez-faire approach to flea beetles as well as Japanese beetles. I’ll keep in mind that established plants tolerate 10 to 30% loss of leaf area without ill effect.

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Sometimes it pays to look closely at your garden plants; sometimes it doesn’t. My general tack with plant pests starts with offering my plants the best possible growing conditions. This means soil that drains adequately and is enriched with plenty of compost and other organic materials to provide nutrients and a friendly microbial environment. It means providing water, as needed. And it means allowing for adequate plant spacing and light. Still, it’s a wide world of insects, fungi, bacteria, and viruses out there, as well as capricious weather, so there’s no reason to expect perfection from each leaf and fruit. Much damage is nothing more than cosmetic and is tolerated by plants. 

One nicety of home-grown fruits and vegetables is that there’s no monetary profit needing to be optimized. So some amount of damage is, and also should be, tolerated by us home gardeners.

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EASY CHERRIES AND A GREEN ROOF

My Nanking cherries (Prunus tomentosa) made a lot of people happy this year. Joy was first spread in early April as thousands of pinkish white flowers burst open along the stems, enough to almost completely hide the stems. Passers-by enjoyed the hedge of plants, which run along the driveway; some people even asked about the name of the plant.

In early June, the blossoms morphed into small, red cherries, oodles and oodles of them. Now, the end of June as I write, just a few cherries still cling to the stems. Throughout the month of June, though, friends, strangers, relatives, birds, chipmunks, and creatures unseen feasted on the abundance.

Nanking cherries are admittedly small and somewhat hard to harvest because they cling closely to the stems on short stalks, but these two deficiencies are far offset by the care the plants need. Almost none! Every few years, I whack back some stems that become decrepit or send the plant high or wide out of bounds.. And I usually spread wood chips or leaves beneath the bushes as mulch to suppress weeds and conserve soil moisture. But neither of these minor tasks is absolutely necessary.

Perhaps the most amazing thing about Nanking cherries is that there are no improved varieties. That is, they are all random seedlings, each a genetic individual. Yet they all taste good, ranging in flavor and texture, depending on the individual, from almost sweet to sour cherry. (Compare this to wild apples, which pretty much all taste bad; the good-tasting apples that we have are the result of hundreds of years of selection and breeding.) Nanking cherry fruits are small, as are the wild cherries from which cultivated cherries are derived.

One of my bushes yields cherries that are slightly larger, slightly firmer and, hence, easier to harvest, and slightly sweeter than my other 10 or so bushes. Seeds from that bush didn’t get spit on the ground; I collected them for planting. Nanking cherry bushes bear fruit within a couple of years and repeated selection of plants bearing the best fruits could result in bigger and better fruits. Improvements might also come from widening the genetic input with pollen from a wider range of Nanking cherry individuals and even some related species, such as sweet cherry. The combination of Nanking cherry’s tolerance to winter cold, late spring frosts, and insect and disease pests and sweet cherry’s fruit size, sweeter flavor, and firmness would make a plant that was easy to grow with even tastier fruits.

I’ll report back in years to come. For now, run-of-the-mill Nanking cherry is well worth growing and another perfect fruit for ambulant consumption on the way to the front door or to the mailbox at the end of the driveway.

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I have a good excuse for the weediness of one of my gardens: It’s on a roof, not an area I frequently walk past with the opportunity to pull a few weeds. I would have to get a ladder and, because this garden is not to be walked on,  reach in as far as possible. I don’t weed it.

This garden is a “green roof” covering a front porch. Green roofs absorb rainfall and the sun’s heat, insulate whatever is below, and look -- well -- green and alive. The last reason prompted my roof planting about ten years ago.

Original hens-and-chicks laid on roof

But first I had to build the porch roof. Construction was standard -- oak posts and crossbeam with 2 by 8 joists covered by 1 by 6 planks -- except for the covering of rubber roofing bonded to copper flashing provided with weep holes at the lower end. Planting was begun the year before with hens and chicks (Sempervivum spp.) in seedling flats filled with a mix of equal parts peat moss and calcined montmorillonite clay (the latter also known as “kitty litter). That spring I snuggled the flats next to each other on the roof. Setting flats on the roof intact would, and did, prevent rainfall from washing the planting mix and plants down the slope, the angle of which was determined mostly by aesthetics. I wanted the top of the roof just visible from the driveway.

The goal was for the hens and chicks to make more chicks, and those chicks to make even more chicks, spreading to make a dense, blue-green mat over the surface and draping over the lower eave. They didn’t spread thoroughly or fast enough.

Angelina now filling in the roof

It takes a tough plant to survive and grow on this roof. The soil mix is only a couple of inches deep so plant roots are exposed to the full brunt of winter cold and summer heat, and the roof gets only natural rainfall. Because hens and chicks weren’t fully up to the task, I started planting other succulents to fill in bare areas amongst the hens and chicks.

Over the years, the most successful of these plants has been Sedum rupestre ‘Angelina’. Not only does ‘Angelina’ survive and grow under the austere conditions, but she also looks pretty year ‘round. Right now, the plant is a trailing mat of fleshy, pointed, pale green leaves up through which push foot-high shoots capped with clusters of yellow flowers. In fall and winter, the leaves take on an amber hue. The plants root very easily to furnish new ones to fill in the few remaining bare spots. I pluck off pieces of shoots and toss them back onto the roof to eventually root and spread. Very convenient. 

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It’s hard to imagine how weeds have gotten onto my green roof, let alone survive. Birds and wind, no doubt, got the plants there. The weeds include fleabanes and some grasses. Some people tell me that these “weeds” look pretty up on the roof, so maybe they’re not weeds. The fleabanes, now in bloom, hold their white, daisy-like flowers high above those of ‘Angelina’. And, if nothing else, both weeds . . . whoops, I mean plants . . . hold the soil in place as ‘Angelina’ continues to spread.

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SEAKALE, CHUFA, OCA

I’m often questioned, “So what are you growing that’s particularly interesting this year.” It’s a tough question to answer because following the growth of even common plants is interesting year after year, watching how they respond to the vagaries of each year’s weather and pests, changing growing techniques, and other influences. Still, a few plants always elicit a, “You’re growing what?”

Such as, for instance, three edibles: seakale, chufa, and oca. Let’s start with the seakale (Crambe maritima). This plant had been growing at the edge of one of my flower beds for many years but died last year. I never did try eating the plant but had earned a permanent place in the flower bed for its gray-green leaves and attractive sprays of 4-petalled white flowers. Those two characteristics would also rightly land the plant in the cabbage family.

Like cabbage, seakale is edible; unlike cabbage, it needs special treatment before being rendered so. That special treatment is blanching, or shielding the emerging leaves from light to make them more tender and mild-tasting. My plant always seemed too weak to endure such treatment so the plant has been enjoyed only for its good looks. This year, though, I have raised a few seedlings, two of which I planted in the rich soil of the vegetable garden and should be strong enough for a couple of weeks of blanching early next season.

Seakale shoots are too tender for transport so you’ll probably never see them for sale. They were popular in gardens of 200 years ago, though -- Thomas Jefferson’s, for one. If flavor turns out to be the reason the plant fell out of favor, I’ll just continue to grow it amongst the flowers.

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Chufa (Cyperus esculentus) is another edible making a return engagement to my garden. This one makes knowledgeable gardener’s raise their eyebrows because it’s very closely related to a pernicious weed, yellow nutsedge. They’re both the same genus and species. I received tubers from J. L. Hudson, Seedsman (http://www.jlhudsonseeds.net/) who claims that the particular selection that they offer does not become weedy; I confirm that claim.

Chufa’s edible portion are the below ground, almond-sized tubers that have a texture an flavor reminiscent of coconut. So you can grow your own “coconut” even where winter temperatures plunge below zero degrees Fahrenheit. Above ground, chufa (and yellow nutsedge) have a grassy appearance except that rolling one of the clumping leaves between your thumb and index finger reveals the triangular cross-section characteristic of sedges. Grass blades are flat.

The main problem in growing chufa is separating the harvested tubers from the soil. Gravel or small stones are about the same size, and a lot harder on your teeth should you accidentally bite into one in a batch of chufa. My plan is to hose down each harvested clump well and then to stir the tubers in water just enough to let anything with the density of stone settle out first. And chew carefully.

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Oca (Oxalis tuberosa) is perhaps the most interesting new plant in my garden, among edibles, at least. It’s related to one of my worst garden weeds, creeping wood-sorrel (O. corniculata). It’s a staple food of the Andean highlands and an iffy crop, around here at least.

The limitations to growing oca are that it needs a long season and it forms tubers only when days grow short (at which time cold weather is likely to kill stems and leaves). On the other hand, the plant has been cultivated for centuries so there are many varieties. New Zealanders have been enjoying and growing oca (which there are called yams) for about 150 years and their varieties are more likely suited here.

I don’t know the provenance of the oca tuber I planted so it could just take up garden space the whole season then die back leaving nothing of value underground. My plan is to keep it warm in autumn beneath a cover of clear plastic, which would be needed even for the most adapted varieties.

And then there’s the flavor. Many varieties, many flavors, from tart to sweet. Oca is used like potatoes and also eaten raw. In the Andes, super-tart varieties are freeze-dried by being left outside on the ground on hot, sunny days and cold, freezing nights. Stamping on defrosting tubers speeds water removal. Interesting, yes?

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Seakale, chufa, and oca are among perennial vegetables that, once planted, come back year after year of their own accord. Others include black salsify, groundnut, Jerusalem artichoke, ramps, skirret, Welsh onion, and, of course, asparagus. For more about perennial vegetables, see Perennial Vegetables: From Artichokes to Zuiki Taro, A Gardener's Guide to Over 100 Delicious and Easy to Grow Edibles by Eric Toensmeier. 

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