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Holly Needs a Male, and Cold Peppers

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Connecting the drip irrigation to the spigot behind my compost pile today, my eyes fell on five nearby Meserve holly bushes. Which brought my thoughts back to last fall, when I realized that I’ve never seen berries on those shrubs.
Hollies are dioecious plants (“two houses”): some are male, others are female. Only the female plants bear the bright, red fruits that, along with spiny, shiny leaves, are so essential a decoration for the winter solstice. To bear fruits (which are ripened ovaries, the female flowers must be dusted with pollen from male flowers.
Last fall, I reasoned that the lack of berries could be that the plants were too young (no, I planted them over 15 years ago), that the plants were too shaded (if so, there would have been at least a few berries), that late frosts were killing the blossoms (unlikely every year), or that the planting lacked a male stud. Except that I do remember making sure to plant one male holly for the harem of females.
A female holly flower
As luck would have it, coincidental with my connecting the drip irrigation, the hollies were in bloom. The blossoms are ornamentally insignificant but did provide the opportunity to confirm each plant’s sexual orientation. No magnifier was needed to see a swollen, green ovary at the base of the petals of each flower on all my plants. All my hollies are females. 
Right away, I started thinking of where, locally, I’ve seen hollies from which I could beg a few male blossoms, assuming other plantings have some males loitering about. Male flowers on a branch with its base in water would stay viable long enough for bees or me to effect pollination.
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Once the drip irrigation was connected, I broke tradition, neglected my own advice, and planted out tomatoes, peppers, and eggplants transplants. The date was May 19th rather than my usual end of May planting date. These plants allegedly shudder at a temperature below 50°F., which was predicted and sure to occur again. I did offer them some protection in the form of light, air, and water-permeable “row covers” held up over the plants by double metal hoops (from www.gardeners.com or, as concrete block truss reinforcing wire, from a building supply store). A single hoop over the row cover at each double hoop holds the row cover in place while allowing it to slide up and down for access to the bed.
Like holly berries, peppers, tomatoes, and eggplants are ripened ovaries — that is, fruits (botanically speaking; horticulturally and legally, they are considered vegetables. As fruits, they need pollination to develop. The flowers, in this case, are monoecious (“one house”), with male and female parts on the same plant. More than that, male and female parts are on the same flower; the flowers are all bisexual.
Pollen still has to move from the male parts of the flower to the female parts, and mostly, it’s bees that get that job done. Bees can’t get at plants within the row cover tunnels so once cold weather is reliably past I plan to uncover the rows and let bees work the blossoms.
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Row covers can also offer protection from certain pests. Anyone who grows eggplant eventually becomes familiar with flea beetles and the holiness they impart to the plants’ leaves. New growth on vigorous plants can more than offset older leaves’ loss of greenery but flea beetles can kill weak plants.
So the tack here is to keep eggplant plants under row cover until their flowers begin to open. In addition to fending off flea beetles, the additional warmth and calmer environment beneath the covering spurs growth for earlier harvest and for a plant better able to fend off flea beetles once uncovered.
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With peppers, it’s especially important to pull off the cover just as soon as plants blossom. The atmosphere within a row cover tunnel is a few degrees warmer than ambient, which is helpful now, when some protection from cold nights might be needed. Fruit set for peppers is poor at temperatures below 58°F., so a little extra heat can improve early season fruit set.
As days grow warmer, the even warmer environment beneath a row cover can have the opposite effect. Fruit set is also poor when daytime temperatures rise above 85°F.
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Tomatoes could remain covered throughout the season because bees are not necessary for pollination. Abetted with just a little movement — from wind for example — the mere opening of the flowers effects pollination. Night temperatures from 59 to 68°F. are best for tomato fruit set. Once night temperatures go higher than 70°F., fruit set suffers, but that’s not going to happen for a long time, even beneath a row cover.

Holly Needs Sex

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LEE’S UPCOMING LECTURES/WORKSHOPS
•Jan. 9: Minnesota Nursery and Landscape Association, Minneapolis, MN, “Weedless Gardening”, “Luscious Landscaping, with Fruiting Trees, Shrubs, and Vines”
•Jan. 23: Long Island Horticultural Conference, Ronkonkoma, NY, “Pruning Shrubs”
•Jan. 25, Northeast Organic Farming Association of New York, Saratoga Springs, NY, “Growing Figs in Cold Climates”, “Espalier Fruits”
•Feb. 6, Indiana Museum of Art, Indianapolis, IN, “Multi-Dimensional Vegetable Growing”
•Feb. 15, Northeast Organic Farming Association of Vermont, Burlington, VT, 
“Grape Expectations: Everything From Choosing Varieties to Eating the Berries”, “Pruning Fruit Trees, Shrubs, and Vines”
•Feb. 20, Ontario Fruit and Vegetable Convention, Niagara Falls, CA, “Uncommon Fruits with Commercial Potential”
•March 1, Northeast Organic Farming Association of Connecticut, Danbury, CT, “Growing Figs in Cold Climates”, “Multi-Dimensional Vegetable Gardening/ Farming”
•March 15, Connecticut Master Gardener Conference, Manchester, CT, “Fruits for Small Gardens”
AND NOW, ON TO HOLLY’S PROBLEMS
The problem is obvious: No sex. No sex, no berries. Oh, did I mention that I’m writing about hollies, my hollies? Now, after a number of years, the plants have grown lush with spiny, forest-green leaves. But no red berries.
A holly berry, like any other fruit, is a mature ovary, which is a home for a seed or seeds. Seeds are what stimulate development of a fruit, but seeds themselves usually can’t get started without sex. Sex happens in plants when male pollen lands on the female part of a flower, called the stigma, and then grows a

pollen tube down the style, which is attached to the stigma, to reach and fertilize an egg. The product of successful pollination and fertilization is a seed, the development of which induces the surrounding floral part to swell to become a fruit.

Why all this concern with holly’s sex life? After all, I don’t give sex a second thought when growing tomatoes. I plant whatever varieties I want and then reap plenty of swollen ovaries . . . er, fruits . . . as well as, incidentally, seeds.
Holly is special because its pollen is borne on flowers that are strictly male and its eggs are contained within flowers that are strictly female. Each tomato flower, in contrast, is botanically “perfect,” with both male and female parts, so can take care of itself, sexually speaking. Similarly self-sufficient are rose flowers, peach flowers, sunflowers, and the flowers of many other plants.
Holly is not alone in having single sex — botanically, “imperfect” — flowers. Many nut trees, for example, share this trait. But holly goes one step further sexually, with whole plants being either male or female, a trait shared by ash and persimmon trees, among others.
The long and the short of it is that I need an all-male holly tree or bush if I’m going to deck my halls with (berried) boughs of holly from my all-female holly tree or bush. A male plant, all leaves and no berries, is not as showy as a female, so it’s fortunate that a single male can sire a half-dozen or so females.
Adding to their sex problems, or, rather, our problems with their sex life, hollies are not all that promiscuous. A few different species supply us with berried boughs — notably American holly, English holly,

My sex-less hollies

and Meserve holly — but, generally, each keeps fidelity to its own species. (An exception is that English holly can pollinate Meserve holly, which is a hybrid offspring of the English species.) Further compounding hollies’ sex problems, some males within a species cannot even adequately pollinate some females within the same species because their bloom times do not overlap.

Breeders have come up with a number of virile male varieties whose genders are obvious from their names: Blue Prince and Blue Boy Meserve hollies, and Jersey Knight American holly are examples. These males, as you might guess, are particularly good mates for the varieties named, respectively, Blue Princess, Blue Girl, and Jersey Princess.
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The hollies that I planted were Meserve hollies. I’m pretty sure that I planted a suitable male for my 5 females, with the male sufficiently close to do their thing with the females. So, why no berries?
One possibility is that my hollies had sex, but that late frosts caused fertilized flowers to abort. But every year? My hollies have never sported berries. One hundred percent frost damage every year is unlikely, and especially so this past spring.
The nursery could have mislabeled their plants. The only way to sex the plants is to peer closely at the small flowers early next May and look for those with male or female flower parts. I’ll do that.
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Sex is no problem for my jasmine (Jasminium officinale) plant; its problem is sexuality. The plant lacks flowers, and flowers are all I ask for from this plant. This plant, commonly known as poet’s jasmine, is supposed to sport oodles of deliciously fragrant, starry, white blossoms about now. (Now that I think of it, perhaps the hollies have never flowered no flowers, no sex, no berries.)
Like amaryllis, Christmas cactus, and many other winter-flowering plants, poet’s jasmine initiates flower buds in response to changing conditions such as exist in late summer and early fall. To whit, shortening days,

My flowerless jasmine

cooler temperatures, and/or, in some regions, drier weather. I’ve tried them all with my poet’s jasmine, and every year about midwinter, buds begin growth on the plant that keep stretching out into lanky, twisting shoots that try to grab onto whatever they can twist around. But no sign of flowers or flower buds.

It’s time to threaten the plant. No flowers this winter and into the compost you go, my little jasmine. (I’ve also tried threatening in previous year, to no avail.) Any suggestions??