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FRUITFUL FUTURES

Making the Best of It

Eek! Mice (or rabbits)! Not the animals but the damage they have wrought. The bark on virtually all my pear grafts of last year has been nibbled off enough to kill the grafts.

Once I calmed down, I realized that all was not lost. All the chewing was above ground level, leaving a small amount of intact bark still in place. The plants aren’t dead, just their portions above the chewing. The near-ground portions could be grafted again.

Daisy showered with petals (more on this later)

Daisy showered with petals (more on this later)

(Most fruit trees neither come true from seed nor root readily from cuttings, so are propagated by grafting a scion — a short length of one-year-old stem — of the desired variety onto a rootstock. The rootstock is the same kind of plant as the scion variety and could be a seedling or a variety developed for special rootstock purposes. My nibbled trees are pear trees, Highland, Blake’s Pride, and other varieties, each grafted on a rootstock named Old Home X Farmingdale 87, which dwarfs the trees’ final height to about half that of a full-size pear tree, as well as induces it to yield its first fruits sooner.)

Damaged rootstock

Damaged rootstock

Crouched way down at ground level would be a tough position for grafting, not to mention trying to keep dirt and debris off the cut surfaces. So I dug up each plant for “bench grafting,” so named because it’s done at a bench or, more generally, upright and in the comfort and better light of indoors.

My graft of choice for these wounded plants is the whip graft. It’s a simple graft, especially for apple and pear; I typically expect 95+ percent “takes.” With a well-honed, preferably straight-edged (and preferably single-bevelled) knife, I make a smooth, sloping cut about 3/4-inch long on the rootstock. Typically, I would make the cut longer but there’s not that much viable stem above-ground. 

Making the cuts on rootstock and scion

Making the cuts on rootstock and scion

Next, I take a scion of similar thickness to the rootstock, although this is not all-important, and make a similarly smooth, sloping 3/4-inch long cut.

If the cuts are secured face to face and then sealed against moisture loss, cells at the cuts start to multiply, eventually knitting the two pieces together and joining their vascular tissue. If the two plant pieces are not matching in thickness, success can still be achieved if just one side of the two of them is aligned. A piece of rubber, either a cut open rubber band or a bona fide grafting rubber, keeps cut edges of scion and rootstock intimate, and then the wound is sealed with Tree-Kote or similar tree wound material, or Parafilm tape.
Cuts on stock and scion in place
Wrapping the graft

Sealing the graft with Parafilm

Sealing the graft with Parafilm

Keeping the roots moist and the plants indoors for a couple of weeks speeds growth of new cells. After that, the plants will go outdoors, either potted up or planted in the ground.

The Downside to Low Grafting

Grafting so low on the plant does have its downsides. For one thing, a certain amount of rootstock stem above ground level is needed for the dwarfing effect. For full effect, grafts are usually made 6 to 12 inches above ground level.

Also, if a graft is very low on a plant so that over the years it gets covered with soil, the scion is could eventually root. At which point the dwarfing and other benefits of the rootstock are lost.

On the plus side, if any of my grafts fail, the still viable rootstock will undoubtedly send up a new shoot, which can be grafted next spring — and done well above ground level.

So How Do You Get a Rootstock?

The way to get a rootstock is to buy one (ha, ha). But how does as nursery make, for instance, an Old Home X Farmingdale 87 pear rootstock if pears (and most other tree fruits) are so hard to root and don’t come true from seed.

Rootstocks are bred or selected to impart special characteristics to the tree for which they provide roots and a short length of stem — very short stems in the case of this week’s pear grafts. Another characteristic that might be sought in a rootstock is ease of propagation, perhaps even by cuttings.

Whereas a pear variety such as Blake’s Pride is propagated from mature, fruiting wood, a rootstock might be propagated from juvenile wood, that is, wood that that has never grow to maturity. All plants are easier to multiply from juvenile wood. Near the base of a plant that has been raised from seed, the wood retains its juvenility, so a seed-propagated rootstock variety that was repeatedly cut back would provide stems that were juvenile and could be rooted as cuttings.

And there are other ways to coax new plants from an existing plant, such as tissue culture and stool layering. Maybe something about these methods at another time.

Fruitful Near Futures

Even grafted higher atop a rootstock that imparts precocity, my pear grafts aren’t apt to yield their first crop for a few years. My Nanking cherry bushes (Prunus tomentosa), on the other hand, are slated to have bright red cherries arching their stems to the ground in a couple of months or so.

A profusion of Nanking cherries!

The cherries are small, but are very juicy with a refreshing flavor that combines that of sweet and tart cherries. Another plus for these plants is that they are more or less free of pest problems, requiring no care on my part beyond picking the fruit. Read more about them in my book Landscaping with Fruit.

No need to ignore the bushes until payday because payday is also right now, visually. Along the length of my driveway, the hedge of Nanking cherries has turned into a cloud of dense, slightly pink, white flowers. This time of year it’s not uncommon for a biker or walker to stop and ask the name of the plants. “Nanking cherry!”

Nanking cherry hedge

Nanking cherry hedge

RATIONALITY CHALLENGED

New York Avocadoes!?!?

    I make no claim to be rational in my gardening — especially this time of year. This thought comes to mind as I look closely at two avocado plants sitting in a sunny window. “Nothing irrational about growing avocado plants in New York,” you might say. After all, the large seeds are fun and easy to sprout, and the resulting plant adds some tropical greenery indoors.
    My two plants were run-of-the-mill avocado houseplants until I took knife to them.
    Let’s backtrack . . . Among my regrets of not living 1,000 miles or so south of here is not being able to harvest my own citrus and avocados. (Also, no outdoor gardenia shrubs or southern magnolia trees here.) A few indoor citrus plants do call mi casa sus casa. But no avocados.Avocado grafts
    From seed, an avocado would take a long time before it bore its first fruit. And especially long under less-that-ideal northern conditions, including indoors in winter.
    And worse, when the plant does finally flower, it might not bear fruit. Avocados generally need cross-pollination because the pollen isn’t ripe at the same time that the female stigma is receptive. Avocado pollinators need to be fairly specific, so that one plant’s pollen is in synch with another plant’s stigmas.
    And even worse, after all that time and hoping for appropriate mates, fruits that do form might not taste good. They wouldn’t be selected clones, such as the delectable Haas or Mexicola, but seedlings. (Plant a seed from a good tasting apple and the resulting tree has only one in 10,000 chance of bearing a good-tasting fruit.)
    Which is why I took a knife to my two avocado seedlings, to graft them to known, good-tasting varieties that are pollination compatible. A friend in Florida overnighted me scions — pencil-thick stems, with leaves stripped — cut from his Marcus Pinkham and Lula avocado trees. One of my seedlings got a whip graft of Marcus Pinkham; the other got a side-veneer graft of Lulu.
    I coverWithed both grafts with plastic to maintain humidity, and every day peer at the scions hoping to see some swelling in preparation for growth.
    Rational gardening? No. After all, even if all goes as planned, how many avocados could I expect to harvest from two small trees? Still, it’s fun.

Warm. Plant.

    Outdoors, it’s the weather that toys with my rationality. A spate of warm days and great restraint is needed not to plant vegetables. I keep referring to my notes (and the chart I made in my book Weedless Gardening) that tell me when to plant what.
  Planting onions  With yesterday’s 75 degree temperatures, urges to plant were satisfied — for that day, at least — by my poking holes into the ground into which I dropped onion plants sown indoors on February 1st. Three-hundred of them in a 20 foot long by 36 inch wide bed. (This was later than the April 21st onion planting date specified in my book, but the weather was cold so I forgot to look at my book.)

Planting Break. Turn Compost.

    When I get tired of planting, I can always turn to turning my compost piles.
    Not that compost piles have to be turned. In contrast to other fermentations, such as bread-making and wine-making, compost always comes out right. Pile up any mix of organic (living or once-living) materials, and eventually you get compost.
    I turn my compost piles so that materials on the outside of the pile get to be on the inside of the pile, second time around. This makes for a more homogeneous finished product.Turning compost
    I turn my compost piles to better monitor their progress, so adjustments can be made, as needed, and to get some idea when they’ll be ready for use. Occasionally, a pile will have a dry region; it gets watered. Occasionally, a mass of material needs to be broken up to better expose it to moisture and microorganisms.
    I also turn my compost piles because it’s good exercise and it’s interesting. But, like I wrote, turning a compost pile is not a must.

TOTIPOTENT — NOT WHAT IT SOUNDS LIKE

 Cells Beget Plants, or Animals

   As I strode out to the garden today, the word “totipotency” was forefront in my mind. No, I wasn’t thinking of myself as “all powerful,” which is what totipotent (Latin totus=whole, potent=powerful) might seem to mean.
    Totipotency is the ability of any cell in an organism — you, me, my dog Sammy, my rose bush — to potentially give rise to any other kind of cell of that organism, or to a whole new organism, a clone of the original. Under the right conditions, you could put one of your skin cells in the right environment, and have those cells grow into new skin, toes, eyes — even a whole new you. Fortunately, nobody has yet figured out how to do that with a human.
    (What I wrote is not exactly true. Not every cell within an organism is totipotent. In organisms that reproduce sexually, egg and sperm cells — the germ cells — have only half their complement of genes, so these particular cells can’t be cloned to reproduce non-germ cells or whole organisms.)
    Back to the garden and totipotence . . . Using random plant parts to make whole new plants is nothing new to most gardeners. With stem cuttings, for example, you put a stem into a suitable environment, and it’s induced to grow roots at its base and new shoots, followed by flowers and, perhaps, fruits, above ground. With leaf cuttings, all these new parts spring from a mere leaf.
    Stems and leaves are more than just a few cells. More specialized, but still feasible, is cloning with just a few cells: so-called micropropagation or tissue culture. A few cells are removed, usually from a growing point, and then, under sterile conditions, put into a petri dish containing a medium to supply nutrients and a balance of plant growth hormones. The cells multiply without differentiation into anything special until they are transferred to another medium, this one with an altered balance of hormones, that induces cells to differentiate into leaves and roots. After a period of growth, the plantlets graduate to real soil.
    Micropropagation is a way to create many new, pest-free clones quickly and from a minimum of amount of mother plant.

Apolitical Graft

    My foray into “totipotencing” plants today required pretty much nothing more than pruning shears. I was cutting scion wood, which are stems for grafting onto growing plants. In this case, the growing plants — the rootstocks — provide roots to the clone; the completed plant, from the graft upwards, is the clone, in this case various varieties of pears.

Watersprouts on old apple tree

Watersprouts on old apple tree

    In the past, I’ve done a “Henry IVth” on pear trees whose fruits were not up to snuff, then grafted a more desirable scion on to the decapitated trees. Today’s scions are for grafting onto one-year-old pear seedlings, to make new pear trees. (Not that I need that many pear trees. The grafting will be done by participants at a couple of grafting workshops I’ll be holding this spring. Stay tuned to my website for when, where, and other details.)
    Grafts are most successful with young scions — one-year-old stems, those that grew last season. They come in various sizes, depending on their vigor; pencil-thick is about right. I cut them into foot-long lengths. Watersprouts, those vigorous, vertical branches often appearing in the upper parts of a tree, are good for scionwood, and most, anyway, should be removed.
 

Pear scions

Pear scions

  The odds for success are also increased if grafting takes place with dormant scions grafted on rootstocks that are either dormant or awakening. That’s why I collected scions today; they’re still dormant, but not for long, outdoors.
    I’ll keep those scions dormant with cold, in the refrigerator or my mudroom (north side of the house, tile floor over concrete).
    Drying out would spell death to the scions, as it would to any living plant or plant part. They need to be kept hydrated, but not in so moist an environment as to cause rotting. So I store them in a plastic bag, around which I wrap a moist towel, and then put the towel-wrapped bag into another plastic bag, well-sealed.

I Was Wrong About Arnold

    I was wrong. Back in December, I wrote, “My Arnold’s Promise witchhazel usually flowers in March. This year’s October flowering means no flowers this coming spring.” Well, it’s March 1st as I write this, and Arnold’s Promise is showered with strappy, yellow blossoms.

Witchhazel's winter flowers and remains of fall flowers

Witchhazel’s winter flowers and remains of fall flowers

    Evidently, not all flower buds slated to open this month opened prematurely, last October. Some did as they are supposed to do: waited. Why? Good question. Looking at the shrub, a location effect does not seem to come into play. Late winter blossoms seem randomly distributed rather than concentrated on older, younger, lower, higher, southern, or northern stems.
    With no explanation coming to mind (yet!), I’ll just relax and enjoy the unexpected show.

Whip graft close up

Graft, The Good Kind & Tomatoes Galore

Reminders:
PRUNING NUT TREES lecture and demonstration, April 26th, at New York Nut Growers meeting. http://www.nynga.org for more information.

GRAFTING WORKSHOP, here at the farmden, on May 3rd. Theory, demonstration, and graft and take home your own pear tree. Contact me for more information.
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  Pest problems, due mostly to having a poor site and living east of the Rocky Mountains, have made me give up on growing apples — almost. Last year’s cicadas and this winter’s deer took their toll also. One problem, I realized, is that my trees are super-efficient, super-dwarfs that I made by grafting chosen varieties on special rootstocks. The problem is that super-efficient, super-dwarfs are also super-finicky about growing conditions. So I decided, instead, to try semi-dwarf trees that would be more tolerant of a less than perfect environment.
Long story short: I’m going to replant with five varieties of great-tasting apples — Macoun, Pitmaston Pineapple, Hudson’s Golden Gem, Ashmead’s Kernel, and Liberty — on G.30 rootstock. Unfortunately, such trees are not available anywhere, not even from Cummins Nursery (http://cumminsnursery.com), which specializes in high quality trees of a range of varieties on a range of rootstocks. They do have those varieties (on other rootstocks), though, and they do have G.30 rootstocks, which I bought and received last week.
And so I set about making new trees, by grafting. The graft of choice was a whip graft, an easy graft to make, especially with apple. Grafts done this time of year are called “bench grafts” because they can be done at a bench or table, indoors, at a time when it’s still too early to plant outdoors. As is usual with bench grafts, my rootstocks were bare-root, nothing more than a 18-inch-long, pencil-thick stems with some roots at their bottom ends. Perfect.
Now for the grafts. Step one was to cut through near the top of the rootstock and near the bottom of the scion with a smooth, sloping cut. Step two was to match the cut faces of the two sloping cuts. Step three was to bind them together; I used grafting rubbers but cut rubber bands work equally well. Step four was to prevent moisture loss from the graft. I covered the graft with either Tree-Kote or Parafilm, the latter a stretchy, waxy material.
Step five is aftercare. The completed grafts could be kept in cold storage until ready to plant out. Even better is to expose the graft to warm temperatures for a week or two to promote callousing, which is a proliferation of undifferentiated cells that mark the first step in joining of stock and scion tissue. I potted my grafts up and put them in the greenhouse for good callousing and to spur the beginnings of new root growth from rootstocks.
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Whip grafting is easy; still, certain requirements must be met for success. The rootstock and especially the scion (the stem of the variety for grafting) must still be in their winter sleep, or nearly so. Check. The rootstock and the scion must be sufficiently close botanical kin. Check; G.30 and the various scion varieties are the same species. The cambia, the layer just beneath the bark, of stock and scion must be touching or at least close. Check; I accounted for different diameters of rootstock and scion stems by lining up one side of their sloping cuts.
The grafts will need to be nursed along this year. With good growing conditions, they’ll be ready for planting out next spring. With luck, a sufficiently green thumb, good weather, and three clicks together of the heels of my red slippers, I’ll be biting into a Macoun apple here in four years.
Graft union, after a few years
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I realize today that it’s as much fun to sample varieties of tomatoes as it is pleasurable to eat homegrown tomatoes. That’s one rationale, at least, for my sowing seed of 21 varieties for planting this season.
Why so many, when probably growing 5 varieties would satisfy all my Lycopersicum esculentum needs? That would be Sungold for the best cherry tomato, San Marzano for the best — or one of the best — canning tomatoes, Amish Paste and Anna Russian as excellent eating and canning tomatoes, Belgian Giant for its unique, delectable flavor, and Carmello for good flavor and earliness from a full-size, smooth and almost perfectly round tomato. Okay, 6 varieties.
After last summer’s tomato taste-off, I could not help but also grow Lillian’s Golden, the winner. And Blue Beech, which, besides good eating, makes a uniquely flavored sauce. Brandywine is a top contender in any best tomato taste-off, so I’m trying Black Brandywine. Perhaps its my imagination, but “black” tomatoes all seem to have a rich, tangy flavor. That’s why I also sowed seeds of Cherokee Purple. German Giant and Paul Robeson got good reviews. Valencia is a pretty and flavorful orange tomato. Nepal is very good.
I’m generally averse to planting any new varieties of cherry tomato because Sungold is so far ahead of the pack. (One year I tried 20 new cherry tomato varieties; 18 weren’t worth eating.) Still, the mother of a reader of this column insisted that she grows a very productive cherry tomato with a delectable flavor; I’m trying it, merely labeling it “Cherry Tomato.” I’m also growing Gardener’s Delight cherry tomato, a variety I grew and enjoyed decades ago, and which disappointed me last year. This year’s Gardener’s Delight, from a different source, might taste different. I’m also growing Ping Pong cherry tomato, which I enjoyed — but can’t remember why — when visiting Hudson Valley Seed Library (http://www.seedlibrary.org) last summer.
I also can’t remember why I ordered seed of Weisnicht’s Ukrainian tomato, but I’m growing it.

Graft, the Good Kind

My friend Sara had a question about graft, which made me immediately think of a recent news item stating that, for the first time, more than half of the members of Congress are millionaires. You rarely hear about graft these days, perhaps because dollars are so ubiquitous a lubricant for our political machinery. No need anymore to elevate the practice with a special word.
But Sara was talking about grafting, not graft, and it was for tomatoes. Apples, peaches, and other fruit trees have been grafted for centuries. Tomato grafting is relatively recent, at least in this country. Sara wanted to know my thoughts about grafting tomatoes and whether we should pool our resources to get some plants.
Grafted tomatoes might grow more vigorously, might be resistant to soil-borne diseases, and/or might be more tolerant of salty, wet, or cold soils. A grafted plant has a specially chosen rootstock — Maxifort, Beaufort, and Emperador are some common ones — upon which is grafted a good-eating variety, often an

heirloom variety. Whether or not, and which, positive traits the resulting composite plant possesses depends on the choice of rootstock. Grafted plants have allowed farmers to keep growing tomatoes in greenhouses and soils where the plants would have otherwise petered out from nutrient problems or buildup of disease.

With decades of grafting fruit trees under my belt, I’d feel confident grafting tomatoes. There are a few differences, of course: tomatoes are grafted when small (with 2 to 4 leaves); they are succulent and in leaf so need to be kept in high humidity until the graft heals; and, best of all, you see results quickly, within a week or two. You start by sowing seed of the rootstock variety followed, a week later, by sowing the scion (eating) variety. Once rootstock and scion plants are large enough to graft, you lay their stems side by side and make an angled cut into both at the same time with a straight-edge razor. Set the bottom cut of the scion atop the top cut of the rootstock and then hold the stems aligned with a tomato grafting clip or piece of tape. After a week or so of warmth, high humidity, and indirect light, the graft should be healed and the composite plant ready to acclimate to brighter light, cooler temperatures, and lower humidity and — eventually — outdoor growing conditions.
An easier but more expensive route would be to purchase grafted tomato plants. Sources such as http://territorialseed.com and http://www.johnnyseeds.com sell grafted plants as well as rootstock seeds and grafting clips.
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Do I want to grow grafted tomatoes? Yes, I’d give the plants a try — if grafted plants of an heirloom variety landed in my lap. Which is to say that I’m not ready to spend much money or effort on grafted tomatoes.
One reason is vigor. Grafted tomatoes grow more vigorously, but my ungrafted, staked  tomatoes always start to grow out of reach by the end of August. More vigor? No thanks. Also, there’s often an inverse relationship between vigor and fruitfulness.
As far as diseases, I avoid planting tomatoes where they’ve grown for the past three years, clean up old stems, leaves, and fruit thoroughly at the end of the season, and mulch each year. In so doing, buildup of soil pests is avoided, overwintering inoculum at the beginning of each season is reduced, and spores of overlooked diseased tissue are buried.
When asking me about grafted tomatoes, Sara probably had in mind late blight disease, which has devastated tomatoes in recent years. Grafted tomatoes offer direct protection only against soil-borne diseases, such as verticillium and fusarium wilt. Around here, at least, early blight, septoria leaf spot, anthracnose, and late blight are what strip plants of leaves and pockmark the fruits. Grafted plants would not be resistant to these diseases.
Increased vigor might help a plant pump out extra fruits in spite of disease — or not. I’m not going to any special efforts to plant grafted tomatoes.
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Apples are another story, one for which I am turning to rootstocks and grafting.
First, a little background: I have an especially poor site for growing apples. Cold or cool, moist air collects in this low spot, making plants prone to disease and frost, and the 6,000 acres of woods fifty feet away provide haven for insect pests. The site is also wetter than I realized. Still, when I do get to harvest apples, their delectable flavor makes them worth the effort.
As with tomatoes, an apple rootstock can impart certain desirable characteristics to the resulting composite tree. My present planting is a row of superdwarf trees. These small trees, although early bearing and productive, need codling with perfect soil. My plan is to make new trees that are more tolerant of less-than-perfect soil conditions and, being taller, might hold their heads in slightly more buoyant air to reduce disease pressure.
Apple has been grown so widely and for so long that many rootstocks have been developed. Thus far in

A young pear graft

my research, a rootstock named G.30 seems the best option, creating a mostly self-supporting (except with certain varieties and heavy crop load when young), medium-sized tree tolerant to wet soil and fire blight disease. Best of all, it promotes of early bearing of the scion variety grafted on it.

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I’ll be lecturing at the NOFA-CT winter conference on March 1st in Danbury, CT. The topics? “Growing Figs in Cold Climates” and “Multi-Dimensional Vegetable Gardening/ Farming.”