Flowers at last!

Isn’t it great to see flowers blooming and leaves starting to show? 

April forsythia, essence of yellow

In my neighborhood, it’s graceful magnolias, heart-lifting yellow masses of forsythia, and flowering cherries, some romantically asymmetrical like inhabitants of Japanese scroll paintings. 

Magnolias, briefly celestial

    In my front yard the groundcover (Vinca minor) is sporting periwinkle blue flowers among the truer blue of glory-of-the snow (Chionodoxa luciliae). 

Vinca puts on its spring show

The first daffodils and hyacinths have opened. Despite my protests that spring came late, this is all happening exactly on schedule. In my yard, the last week of April is the official start of the outdoor garden season. 

Daffodils among the vinca

    I’ve been struck this year by the beauty of the first tree flowers, not just the ornamental trees with big flowers like those magnolias. Red maple buds (Acer rubrum) have opened to reveal batches of tiny deep red flowers along the twigs. 

Red maple in bloom

This tree has male and female flowers, sometimes on the same tree. By the time the leaves start to open, the fertilized female flowers will already be ready to strew their whirly seed pods, called samaras, on May sidewalks.

Red maple seeds pods

A fascinating study by local biologist Richard Primack elucidated the somewhat fluid gender distribution among 79 red maples in a nearby park. He found that while 75 percent of the trees were male and 23 percent were female, 2 percent varied from male to female from year to year. Of the 77 consistently male or female trees, 12 showed a few flowers of the opposite sex some years. So apparently maples refuse to be defined by the gender binary.

    As much as I curse the ever-so-fecund Norway maple (Acer platanoides) and wish it had never been chosen as a street tree, I find its lacy flowers beautiful, especially seen against streetlights on warm spring evenings. 

Even Norway maples have intriguing flowers

Later we’ll see the dangling flowers of the oaks as these trees prepare to leaf out, last among our local deciduous trees.

A red oak twig

    I’ve been focusing a lot recently on flowers that need insect pollinators, because those insects are essential at the base of the food web for all us animals on earth. Maples, oaks, and lots of other trees don’t have to attract pollinators. They can rely on the wind for pollination, although their pollen can be an important early food for insects such as bees when little else is blooming. 

     That’s why these trees don’t have to make showy, colorful flowers with insect-attracting tricks such as ultraviolet runway markings pointing the way to the “nectar reward.” They just hang out their stamens in open air so that the wind will catch the pollen. That’s also why they make so much of that pollen, as seasonal allergy sufferers are well aware.

     I find that as time go by, I’m more drawn to the subtle flowers of these trees and less to dinnerplate dahlias and their like. Small can be elegant.

Live and learn

This year more than usual is riding on my plant propagation. As part of an ongoing quest to publicize my book, The Sustainable-Enough Garden, I'm planning to participate in our local farmer's market, selling gift baskets for gardeners that contain six-packs of herbs and edible flowers, along with the book and other fun items. I'm starting more seeds indoors than usual, and I'm worrying about them more. If I can't produce the seedlings, then what?

Purple and green basil--will they be ready for market?

    I’m learning first hand that production growing is fraught with many pitfalls. What’s enough water, and what’s too much? Exactly when should I plant each variety to have little plants the right size by June 30, the first market date, and through the summer?

Tarragon cuttings are doing well (left), but only one of 24 seeds I planted germinated (right). Why?

Transitioning the seedlings outdoors to “harden off” will be an anxious experience with many questions regarding correct timing. This growing is like mothering, with all its uncertainty and need for constant vigilance.

    This week I came back from eight days on vacation away from my seedlings fearing heavy attrition. Would they have wilted and died without watering? I’d moved all the seedlings to the basement, figuring they’d need less water in a cool space where evaporation would be slower. 

     I followed the advice of one of my gardening heroines, Thalassa Cruso, for getting houseplants through times when no one’s at home to water. She recommends covering them with plastic sheeting to minimize evaporation. I adapted this for my seedlings by using some rigid clear plastic covers sized to fit over the seed trays. 

A clear plastic cover made for the seed tray is convenient

When I ran out of those, I cut open old dry-cleaning bags to drape over the little plants.

A repurposed clear plastic bag works too

    In the bottom of each tray, under the six-packs that hold the seedlings, I’d already placed a layer of capillary matting, absorbent synthetic fabric that gradually releases water to the pots.  I made sure to water the growing medium and soak the capillary matting before I left town.

Spongy fabric absorbs water and releases it gradually

    As soon as I got home, I pulled off the plastic to check on the little plants. Most of them were fine. I was surprised to find that the growing medium was still moist in many of the six-packs, and much of the matting was still wet. Moss or algae was growing on the surface of the growing mix in some of the pots. That showed how humid it had stayed inside the plastic enclosure, but it didn't seem to be doing any harm.  

    I’d managed to kill some cuttings I’d taken from a rosemary plant I brought indoors last fall. I’d left these uncovered because I thought they’d rot under the plastic, and I hadn’t set their six-pack on wet matting either. Unsurprisingly in retrospect, four of the six dried up, dropped their leaves and died.

News flash! Plants need water to survive

    Lots of questions remain. Clearly farming requires expertise and experience that I don’t have. Even if my farmer’s market project fails, I’m bound to learn a lot this year.

It's spring! Cornelian cherry (Cornus mas) blooming at last

Sex, drugs, and plant propagation

Which is better, sexual or asexual reproduction? It depends who’s doing the reproducing. This spring I’m making new plants both ways. Seeds are produced through sexual reproduction. Each seed has two parents with different genetic make-ups. That means each seed, and the plant it grows into, is a unique individual, like us. I’m growing a lot of my new plants from seed, including vegetables, herbs, and annual flowers.

Each borage and basil seedling is a genetically unique

    Asexual reproduction accounts for a lot of the perennials, trees and shrubs we buy. If you’re a breeder who wants to make sure your dogwood or azalea is exactly like its parent, you clone it. Unlike human tissues (so far), plant tissues have the ability to reproduce whole plants from parts of the parent plant.

A desirable rhododendron can be cloned infinitely

     Right now I’m growing cuttings from last year’s rosemary, bearberry (Arctostaphylos uva-ursi), and coleus. I’m hoping to do the same with tarragon and oregano I bought at the garden center. If these cuttings take root and grow, the plants they grow into will be genetically identical to the parent plant.

Cuttings from bearberry and coleus are clones

I’ve read that some named shrub varieties consist entirely of clones from one desirable plant. Many plants, but identical genes.

    People concerned about biodiversity have a problem with this system. In addition to encouraging us to grow native plants, they want us to foster genetic diversity among plant species. The reason is that a broader gene pool allows a species to adapt to changing environmental conditions. Some individuals in the population will develop greater resistance to heat, drought, flooding, and other challenges. As climate change speeds up changes plants face, they need to be ready to evolve in response.

    There’s an inherent tension between promoting biodiversity and maintaining desirable varieties. If you’re trying to grow a particular tomato, say ‘Brandywine,’ which is open pollinated (not a hybrid), you don’t want your ‘Brandywine’ plants fertilized by pollen from other tomato varieties. 

Tomato growers want to keep varieties distinct

     But if you’re just growing a patch of perennials, say native purple coneflowers (Echinacea purpurea), there’s no reason not to let them mix with nearby members of their species and create a genetically mixed population. In fact, your stand of coneflowers will be more likely to survive if it includes members with different genes that can tolerate varying conditions.

A genetically diverse coneflower population is adaptable

    Except for letting willing self-seeders do their thing, I haven’t propagated perennials from seed. When I want more, I may divide the plants or, as with rosemary, bearberry, and ivy, grow more from cuttings. If a snippet from the growing end of a plant is willing to send down roots, why not make more that way? Divisions and cuttings make clones, just as tissue cultures made by breeders from a few cells grow into clones of a newly-developed perennial. In future I want to learn to grow native perennials from seed so I can help maintain their genetic diversity.

Felix, a new garden helper visiting from New York

I’m off on a trip to the Southeast, hoping to experience spring flowers there and again at home when I return. See you in two weeks.

Fiat lux

With my old fluorescent grow lights getting dimmer month by month, I decided it was time to upgrade the lights I use for fostering my seedlings in the basement.

The more light they get, the stronger seedlings will be when it's time to move outside

    Although we may like the idea of starting seeds on a sunny windowsill, the sunlight that comes through a window isn’t really bright enough to grow strong seedlings. Even if I had an unobstructed south-facing window, which I don’t, plants couldn’t get more than 6,000 lux through the glass. In comparison, outdoor light can reach 120,000 lux in full sun.

Light through the window isn't strong

     As plants stand farther back from the window, available light drops off quickly to only 3,000 lux at one foot. Screens filter out light too, and short winter days reduce light exposure.

    Artificial light does more for seedlings that are destined to grow outdoors. My young plants will need 20,000 to 25,000 lux to grow robustly.

Shorter and chunkier is better

    For years I’ve used fluorescent lights for my seedlings. My first set-up was a cheap fluorescent shop light hung from a board held up by bricks. It did the job. Later I bought a four-shelf unit with two fluorescent tubes at each level. The lamps could be moved up and down, which was convenient for keeping them no more than six inches above the leaves—again, light levels drop off sharply with distance from the source. The bulbs didn’t generate heat; even leaves touching them came to no harm. I could use regular fluorescent tubes for these lamps or choose tubes that offer a color spectrum favored by growing plants.

    Over the years, I’ve had trouble maintaining these fluorescent fixtures. Replacing the bulbs and the starters that are needed for fluorescents turned out to be tricky. This winter I was down to one and a half working lamps.

    Meanwhile, for upstairs I upgraded to a T5 fluorescent, twice as intense as the T12s in those basement lights. I can appreciate the difference. The light looks brighter, and seedlings stay huskier under it.

T5 fluorescent under a windowsill

    Marijuana growers may opt for the even greater intensity of HID (high intensity discharge) bulbs, metal halide or high pressure sodium. This is the very bright light you’ll see in clandestine windowless growing areas in TV crime dramas. My friend Prudence urges me to try growing marijuana, but I’m not up to that level of indoor production yet. HIDs generate a lot of heat, which means you can’t let leaves get as close to them. 

    The next wave in grow lights is LEDs. The Gardeners Supply catalog offers LED light stands for around $250 to $300 per shelf. That’s more than I wanted to spend. Instead, I bought a heavy duty wire shelving unit and four LED shop lights—total cost $280. 

New LEDs. I hung some lamps at an angle to keep them closer to the foliage.

It was easy to hang the lamps from the shelves with the hardware provided. They certainly provide more light than the fluorescents, and they should last for my lifetime. Will their light spectrum work for my seedlings? Stay tuned.