Espalier pear tree

APICAL DOMINANCE — WHAT FUN!

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Suppression & Stimulation

“Apical dominance” sounds sadomasochistic, but no reason to shudder: it’s practiced by plants and, even when carried to an extreme, results in something as agreeable as a head of cabbage. True, we gardeners sometimes have a hand in apical dominance, but it’s still just good, clean fun.

Look upon it as hormones gone awry or as hormones doing what they’re supposed to do; either way, apical dominance is the result of a hormone, called auxin (AWK-sin), that is produced in the tips of growing shoots or at the high point of stems. Traveling down inside the stem, auxin sets off a chain of reactions that puts the brakes, to some degree, on growth of side shoots, giving the uppermost growing point (the apical point) of any stem the upper hand in growth.

Side shoots mostly arise from buds along a stem, and whether or not a bud grows out into a shoot depends on how close the bud is to the source of auxin; the closer to the source, the greater the inhibition, how far and to what degree depend on the genetics of the plant. ‘Mammoth Russian’ is a variety of sunflower that grows just as a single stem capped by a large flowering disk; with no side branches at all, this variety demonstrates an extreme example of apical dominance. SunflowersAt the other extreme would be one of the shrubby species of willows that keeps sprouting side branches freely all along their growing shoots.

Even within a single species of plants, individuals vary in their tendency to express apical dominance. A fuchsia variety Read more

Fruit in hand and on stem

EASY CHERRIES

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Sweet, Juicy, & Tolerant

Nanking cherries (Prunus tomentosa) are now at their peak of perfection, sweet and sprightly flavored, brilliant red in color, still firm, and, as usual, abundant. Nanking cherries are very juicy and not stingy to release the juice. Straight up, it’s the most refreshing juice imaginable.Picking Nanking cherries

You’ve never heard of Nanking cherries? Understandable since they are an uncommon fruit. (And warranted a whole chapter in my book Uncommon Fruits for Every Garden, now out of print but in the works for updating and expanding.) As the name tells you, they are native to China, more generally to the cold, semi-arid regions of Asia. This provenance tells you something about the toughness of the plant, where it weathers winter temperatures below minus 20 degrees F. and summer temperatures as high as 110 degrees F. Read more

Wisteria flowers

WISTERIA UPS AND DOWNS

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Shoots vs. Flowers

Around this time of year, few plants are as dramatically beautiful as a well-grown wisteria, whose chains of lavender flowers drip like little waterfalls from the branches. I’ve always wanted one, and now I have one. Wisteria flowersBut I’ll keep in mind a common complaint people have with wisteria: The frustration when a wisteria plant is all shoots and no flowers!

This problem has some causes and some solutions. The common complaint can often be traced to something as simple as a poor plant or a poor site. Perhaps Read more

Heath bed from NE

A SLIPPERY SLOPE

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A Little History

Walking down the path alongside my home first thing this morning, I looked to my right and was wowed. What I saw warranted bragging rights. Flowers in red, pink, white, and a touch of purple against a backdrop of varying shades of green leaves, some sparkling with reflected light, others mat, holding onto any reflections. Heart-shaped leaves, lance-shaped leaves, and compound leaves livened the backdrop. All of it set off against the solid backdrop of the red brick wall.Heath bed from NE

Although I chose and planted all that I admired, not too much credit for it was mine. This was no carefully planned design laid out on paper with squiggly shapes representing plants and their locations, each shape labeled with plant names and varieties, perhaps even a note to flower colors.

Twenty plus years ago, the site was a strip of sloping lawn on the east and north sides of my home. Imagining myself one day slipping while mowing with my foot sliding beneath the mower that birthed a plan for building a rock wall at the base of the slope which would be backfilled with soil. No more slope and no more mowing.

The Heath Family Stays Together for a Reason

And so was borne my “heath bed,” a bed of various plants in the Heath Family, Ericaceae. Grouping such plants together was not just a botanical plaything; it had function. Read more

Apricot trees in bloom

A FRUITFUL YEAR?

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High Hopes

Apple, pear, and plum branches frothing in white blooms this spring foretold of bountiful crops of these fruits. Wrong. They foretold of the potential for bountiful crops. I’ve mentioned before the abundance of insect and disease pests that lurk here, ready for action, and the potential for late spring frosts. So I don’t get my hopes too, too high with these fruits, except for the pears, European and Asian, which are naturally pest-free here.

Lots of things can be blamed for a barren fruit tree, bringing disappointment no matter what the cause.

Apricot trees in bloom

Apricot trees in bloom

If the tree is young and not yet of flowering age, fruitlessness can be forgiven. Pears, for all their qualities, are typically slow to come into bearing.

Who Needs a Mate?

There’s many a slip ‘twixt the cup and the lip. Read more

Cardinal flower

IS IT SUNNY, ENOUGH?

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A Plant’s Perspective

No matter what you’re growing, and especially if you’re growing most fruits or vegetables, you need to know what “full sun” and “part shade” mean. People with shady yards often have their own definitions.

The tall trees that surrounded my father’s yard created lots of shade; he once planted a grapevine in what he called a sunny spot, which was where the leafy tree canopy spread open enough to let a ray of sunlight peek through for about an hour at 12:30. The grape vine did grow, but bore a paltry crop, and those grapes it did bear were sour.

Grapes need “full sun. “Full sun” to a plant means direct, unobstructed sunlight for at least five or six hours a day. Besides vegetable gardens and most fruit trees, many flowers also require this exposure.

Sometimes Shade is Tolerable

There are plants that are well adapted to, even need, shade in their youth, but require more sunlight as they age. Maples and beeches, for example, as well as other forest trees which start out as seedlings in the shade of existing forests, but eventually reach light and become the canopy itself.Forests of maples in autumn color

Pawpaw, which is a forest tree native throughout the eastern part of this country, is also in this category. That applies to seedling trees, that is, trees Read more

Climbing hydrangea

PRUNING HYDRANGEA

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Get hip. Hydrangeas are all the rage these days. If you do have a plant or plants, you may have to prune them. But hydrangea isn’t just one kind of plants; a number of species are popular. Before you approach your hydrangea or hydrangeas, pruning shears in hand, you’ve got to know what species you are growing. They differ in their pruning needs.Climbing hydrangea

Adapting the text from my book, The Pruning Book, I’m going to give you a (figurative) hand by explaining how to identify each commonly  grown species, and then guiding your hand holding the shears.

You’re Probably Growing…

If you grow just one hydrangea, I’ll bet that it’s Bigleaf Hydrangea (Hydrangea macrophylla). This species is most recognizable for sporting electric blue or lively pink flower heads, blue when the soil pH is below 5.5 and pink when the pH is above 6.5. Read more

Juvenile oak trees

BENEFITS OF IMMATURITY

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Old Skirts

Looking at trees that usually drop their leaves in winter, you might notice that some of them — especially beeches and oaks — wear skirts of foliage all winter long. I say “skirts” because if the trees were human, the leaves would all be at skirt-level. Rather than being lush and green, these skirts are dried and brown or gray, just like their counterparts on the ground.

These trees, still clinging to their leaves, aren’t out of synch with the environment. Nor does this habit reflect the effect of climate change or nighttime lighting. The oak and beech branches cling to their leaves because the branches are “juvenile,” and reluctance to drop leaves is one sign of juvenility in plants.

Juvenile oak trees

Juvenile oak trees

(Artificial lighting and a warming climate have been shown, though, to delay leaf drop in autumn and advance the time when leaves unfold in spring, just how much depending on the tree species and the duration and the color of the light.)

Changes with Maturity

Juvenility in plants is akin to prepuberty in humans: during this period plants grow but are incapable of sexual reproduction, that is, flowering, then setting seed. Read more

Cardoon & Fig

LOOKING BACKWARD, LOOKING FORWARD

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Here’s a backward story and a forward story.

About plants, of course. And the plants are linked in that both of them are native to the Mediterranean region. But for centuries, both plants have been grown world-wide wherever winters are mild. And, with some special attention, by enthusiast (such as me), in gardens where winters are frigid.

Perhaps you’ve already guessed the two plants. If not, they are cardoon and fig. Let’s start with the backward story, which is the one about cardoon.

Cardoon & Fig

Cardoon & Fig

A Florific Season in the Offing (I Know It’s not a Word)

The end of the cardoon story begins with my memory of last summer’s very bold plant whose whorl of glaucous, spiny leaves rose three feet or more above ground level. Read more

BITTERSWEET MEMORIES

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I Almost Become Very, Very Rich

My vision became blurred with dollar signs as I looked out the car window at mile after mile of bittersweet (Celastrus scandens) clambering over trees along a stretch of parkway. That was a few years ago, as I was driving away from a visit to New York City. While there, I had wandered into a florists’ shop, where I had been stunned by the price for a few sprigs of bittersweet. A quick mental calculation as I gazed out the car window told me there was gold in them thar’ trees.Bittersweet on trees

My financial empire crumbled before it even had a chance to grow. In some states, bittersweet is a protected plant. Anyone harvesting a protected plant from private property without the landowner’s permission may be subject to a fine.

To look at bittersweet, you might very well mistake it for a weed. The plant is a rampant, fast-growing vine. Given support, it will climb skyward twenty feet or more. Bittersweet can engulf small trees and shrubs, even kill them by twining around, then strangling them.

And bittersweet isn’t found in restricted ecological niches over a small geographic area. The plant grows wild in thickets and along roadsides over an area bounded by southeastern Canada across to the Dakotas, south to Texas, and then back across to North Carolina.

Read more