Wedding white

Dear friends,
I apologize for infrequent posts. I’m absorbed with a happy event, my son’s wedding next weekend. I’ll be back with another post in June. Here’s something I hope you’ll enjoy for the end of May:

White flowers signify innocence, purity, honesty, perfection--and weddings. Whatever the occasion, May’s white flowers are especially beautiful. 

    Before we assume that flowers are white for a biological purpose, we have to bear in mind that from the plant’s point of view, human vision is beside the point. Flowers evolve mostly to attract pollinators. 

    Bee vision, for example, differs from ours. Bees can’t see at the red end of the visible light spectrum, but they see ultraviolet light that’s invisible to us. A flower that looks white to us could show a bee ultraviolet runway stripes (nectar guides) or bullseyes to mark the landing area, holding up a sign that says “Get your nectar and pollen here!”
 
 

Visible nectar guides--stripes on this iris--guide bumblebees to pollen. Photo by Al Schneider

    Each of my white flowers has a different strategy for getting its flowers pollinated and reproducing itself.

    Sweet woodruff (Galium odoratum) is a hermaphrodite pollinated by bees, flies, or itself—no wonder it spreads so fast. 

    Double-file viburnum (Viburnum plicatum var. tomentosum ‘Shasta’) has been fooling visitors this spring into thinking it’s a dogwood because of its horizontal rows of glowing white flowers. These attract insects and humans first with larger, sterile flowers that resemble the “petals” on flowering dogwoods (in fact those are adapted leaves called bracts).

The inner fertile flowers of the viburnum open a few days later.  

    Lily-of-the-valley (Convallaria majalis) is flowering profusely this week. Last year must have been a good one for this plant, because as its leaves emerge this spring, I’m finding it has expanded into new territory. The tiny bells on its flower stalks are pollinated by honeybees and bumblebees.

Each lily-of-the valley needs to cross with a genetically distinct plant to make fruit, one red berry per plant. But anyone who lives with this determined shade grower knows it does plenty of vegetative spreading even without fruit.

    The flowers of dwarf fothergilla (Fothergilla gardenii) have both male and female parts but no petals. I read that they’re pollinated by honeybees. Offering such easy access to nectar, they must attract other insects too. 

Bottlebrush flowers of dwarf fothergilla

    Bleeding heart, a member of the poppy family (Papaveraceae), offers pollen but not nectar to visiting insects. 

White bleeding heart, Dicentra spectabilis 'Alba'

Once the seed develops, bleeding heart has an interesting method for spreading it around. Each seed is attached to an elaiosome, a white fleshy blob rich in lipids that ants like to eat. 

Bleeding heart seeds with attached elaiosomes

Ants carry the seed back to their anthills and eat the elaiosome without damaging the seed. In return, the seed gets a free ride to a location farther from its parent plant than it could otherwise travel.

Quick and dirty

This weekend I potted up my tender perennials using homemade non-peat potting mix. I store dahlias, cannas, elephant ears (Colcasia esculenta), and South American anise-scented sage (Salvia guaranitica) in the basement through the winter and wake them up in spring to flower another season. 

Salvia guaranitica 'Black and Blue'

They’re plants from warmer latitudes that can’t tolerate New England winters outdoors. Because of their large fleshy roots, they can survive out of the ground until spring.

Dahlia tubers after a winter in the basement

     Making this happen is supposed to be more complicated than I’ve found it. For example, my old copy of The Reader’s Digest Illustrated Guide to Gardening prescribes many steps for winter storage of dahlia tubers. The reader is instructed to wait until frost blackens the foliage, cut off stems at 6 inches, carefully lift the roots from the soil without damaging them, use a blunt stick to clear loose soil from the tubers, hang the plants upside down for two weeks to dry, dust them with sulfur to prevent fungal infections, and store them in trays of dry sand or peat moss in a cool greenhouse or dry cellar at 40 to 45 degrees.

    This idea that houses contain rooms or outbuildings that stay at 40 to 45 degrees during the winter seems to be a throwback to English gardening. With central heating and effective insulation, I can’t imagine there are many houses in the northeastern US that offer these special conditions for plant storage.

    I tried the Reader’s Digest authors’ approach one winter (admittedly leaving out the sulfur sprinkling). By spring my tubers had dried up, shriveled and died.

    Instead, I stumbled on a much simpler approach for over-wintering tender perennials. In late fall I cut the stems and dig up the plant, leaving plenty of soil around the roots. I place each plant, soil and all, in a brown paper grocery bag. I enclose this in a plastic drawstring kitchen-size trash bag, tie the top closed, and store it in the basement on wire shelving. There the plants go dormant in darkness and cool-enough temperatures.

    Cultivating dahlias for the biggest, showiest flowers is a special skill that I haven’t acquired. However, I can count on my stored dahlia tubers and other tender perennials to stay hydrated enough to sprout indoors when I replant them in pots in May. I let them grow indoors for a month.

Potted and ready to go inside to sprout in a sunny spot

As the weather warms, I move them outdoors during the day and back inside at night. After Memorial Day I can plant them in the garden or in large containers, where they flower again for another summer.

Elephant ears in July

Dahlias in September

I used to consume many bags of commercial potting mix for this process. Now I get good results with a peat-free mix of half coir (coconut fiber) and half screened compost from my compost piles. I’m glad to leave the peat in its bogs, where it sequesters carbon.

I mix screened compost and coir right where I'll pot the stored plants

 
   

Lawn grass--threat or menace?

Why do some plants grow well only where you don’t want them? Lawn grass in my garden keeps reminding me of this question.

    A few years ago, the water department replaced our old cast iron main water pipe, leaving a big trench in the front yard that city contractors thoughtfully filled with topsoil. Apparently they didn’t notice that the shady area they’d dug up was not lawn—it had already been converted to a bed of periwinkle (Vinca minor). 

Periwinkle replaced our sorry front lawn

Following standard practice, they sprinkled grass seed on the new soil.

    I was amazed at how well that grass grew. I tried to scoop the seed up immediately and replace it with more periwinkle seedlings, but grass still sprouted. It was several seasons before I could weed it out, plant by plant. 

    I noticed the same with grass that showed up in a perennial bed in the backyard. It migrated from the lawn by sending out underground stems toward the bed, and once it established a foothold, it was quite hard to pull out.

Wandering lawn grass  peaking from under a meadow rue

    In contrast, the grass seed I planted in the backyard barely made an effort. Each spring and fall I’d hopefully over-seed my lackluster lawn with expensive seed mixes. To help the new grass plants along, I watered frequently with a hose or rotating sprinkler. One year I even put down a wet slurry of shredded newsprint, fertilizer, and grass seed that was supposed to keep the seed moist until it could sprout in bare patches of the lawn. 

    Each time I planted, a few young blades of grass would sprout, only to die away in the heat of the summer or disappear by the next spring.

    Why was this happening? Was it just my lack of diligence in caring for the young grass? If lawn grass could co-exist happily with periwinkle and coreopsis in planting beds, why couldn’t it also compete successfully with other species in the lawn?
    .
    First, nature abhors a monoculture. I’d watched neighbors completely remove their lawns and reseed. After a year or two, unless they used weed-killers, they were back to the same mix of crabgrass and other weeds that made up my lawn.
 
 

The view from our deck--more weeds than lawn grass

    Second, my lawn’s soil is not hospitable. I don’t pamper it with compost or shredded leaves, we compact it by walking on it, and new grass sprouts don’t have the luxury of shelter from taller plants in their early days. They have little chance to establish a root system before investing energy in leaves.

    Lawn grass is the hardest plant for me to grow. I’m ready to give up. Moss thrives in our acidic soil in the shadier parts of the lawn. It looks quite nice. 

Moss is taking over a shady section of lawn

Bluestone pavers and low-growing perennials would look even better. 

In future I see more bluestone, less grass

Flowers and feathers

In April as my sap is rising, other inhabitants of the yard are out ahead of me getting things done.

To be a good neighbor to native creatures, starting with insects, I’m trying to offer blooms from early spring through late fall. Nectar is useful food for the bugs. I also want to provide the right shelter and reproductive conditions for insects and other animals.

    This week several kinds of small flowers are blooming on the garden floor. They aren’t spring ephemerals; they’ll keep their foliage through the summer. But they’re getting in their bid now for attention from early pollinators. I saw a bumblebee weaving above the flowers today, the first I’ve spotted this year. 

Siberian bugloss (Brunnera macrophylla)

Barren strawberry (Waldsteinia fragarioides)

Labrador violet (Viola labradorica)

Bishop's hat (Epimedium x versicolor 'Sulphureum')

Some early-flowering shrubs and trees are getting in on the act too:

Quince (Chaenomeles x superba)

Serviceberry (Amelanchier arborea)

     Other animals are taking advantage of the warmer weather and longer days. Birds are very active, singing their territorial songs at dawn, feeding and looking for nesting materials all day. 

    Two years ago to help the bird line their nests, I bought a set of “grapevine globes” filled with cotton fiber from Duncraft. This was to invite birds to live in my yard, in hopes that they’ll help create an equilibrium between plants and leaf-eating insects. 

    The vines woven into hollow balls are attractive, but the cotton inside didn’t appeal to the local birds. They never pulled it out, and it gradually matted and discolored in the rain and snow. Birds in my yard are much more enthusiastic about white goose feathers I bought from DownLite Bedding, a company that sells them for topping up feather comforters. 

    Today I was able to poke the feathers through the openings in the vine balls. 

It’s even easier to fill up onion bags with the feathers and close them with twist ties. 

These balls of feathers look strange hanging in the trees, but the birds love them.

There’s a frenzy of activity as they peck out feathers and carry them away to where they’re “feathering” their nests. It’s satisfying to join in the work of spring.

The root of the matter

Walking my dog at a beautiful park along a stretch of the Charles River, I’ve been alarmed to see heavy construction machines demolishing a small playground surrounded by giant mature oaks and pines. My worry is that digging so near the trees to remove the footings of the play structures, the excavators will destroy enough roots to kill the trees.

    Remember that old diagram of a tree sending roots underground as deep as the tree’s height?

   That turns out to be completely wrong. Roots stay near the soil surface, the majority in the top 1 to 2 feet of soil. That’s because they need the oxygen that’s there for respiration. 

The exposed roots of this tree form a shallow disc, not a deep wedge

    You can kill a tree or shrub if you dig too much in its root zone, even superficially. I once assassinated a lovely mature Japanese andromeda (Pieris japonica) by carving a narrow trench all the way around it for plastic edging that I fondly imagined would keep the sweet woodruff (Galium odoratum) I’d planted as groundcover from spreading (it did nothing of the kind).
    That gave me a healthy respect for how far feeder roots extend from the base of a shrub or tree. I’d thought the roots stayed approximately inside the drip line, the outer circumference of the plant’s branch tips. In reality, when unencumbered, roots extend to two to three times the width of the tree. 

    Not that you can never dig a hole near a tree, of course. You just have to think about how much of the root mass you’re going to interfere with. Since the roots radiate out from the base of the tree, the closer you dig to the trunk, the greater percentage of roots you’re going to kill. If a tree loses 40 percent or more of its roots, it will die. 
    So now I don’t like to see a power shovel digging close to the trunk of a tree. Sure, it saves a lot of time and manpower, but the potential environmental cost is too high. 
     It doesn’t help, either, that a heavy dump truck has been parked next to trees at the site I visited. This will compact the soil and reduce air spaces needed to allow roots to take up oxygen, water and nutrients. There’s more sobering information about tree damage caused by construction at the Minnesota Department of Natural Resources website.

 
    The white pines (Pinus strobus) and red oaks (Quercus rubra) along the river must be more than a hundred years old, judging from trunk diameters of almost 4 feet. They shade the playground and the many people who enjoy running, bicycling and strolling along the river bank. They stabilize the soil.

     As native trees, they’re foundational species for communities of plants and animals. They would be a terrible loss, irreplaceable in our lifetime. 

     New playground equipment is a nice idea. I very much hope the trees will survive its installation.
***
For a story of utterly unsustainable gardening, don’t miss this recent post at The Massachusetts Spy

Making the most of early spring

This is one of my favorite times in the garden, when leaves start to show and every day brings new green shoots poking up from the soil. This weekend I’m surveying how my native plants have held up through the winter.

      Among native perennials, I’ve had success with shade-loving spring bloomers that are referred to as spring ephemerals, because they do all their important work early in the growing season. One of the first I tried was white bleeding heart (Dicentra spectabilis ‘Alba’). It sends up stalks of feathery first leaves in early April. The pearly white blooms last into May. 

First bleeding heart leaves

Blooming last May

As the summer comes on, the foliage usually turns yellow and withers. I’ve learned that I don’t have to worry. The plants’ fleshy roots store up fuel for the next year even when little or no green foliage shows after July.

    This strategy allows the bleeding heart to soak up the sun’s energy before the trees overhead have leafed out. The early flowers get lots of attention from insect pollinators, who have few other options at this time of year. Then the plant can go dormant and rest, with minimal metabolic demands, until the following spring. 

     The same approach works for bloodroot (Sanguinaria canadensis), which is just unfurling its distinctive gray-green indented leaves now and opening its white flowers. After ten years in my garden, the original few plants have started to spread. Now I have colonies in shady areas within view of the house. Their appearance is one of the heart-lifting signs that spring is really here.

Flowers opened this week

Bloodroot is making a colony

I’m just getting started with another spring ephemeral, yellow trout lily (Erythronium americanum), also called dog-tooth violet. One of three I planted near a stone birdbath has disappeared, one is limping along, and the third really seems happy. There’s a colony of these covering at least a thousand square feet in a local conservation area, near the banks of a small stream. I’m hoping my few plants will send out lots of offspring. It may depend on their getting enough moisture.

Trout lily getting ready to send up its flower stalk

     Until yesterday I thought I had killed a new native shrub I planted last year, Carolina allspice (Calycanthus floridus). It made it through the summer in fairly dense shade, getting only morning sun. Its dark red blossoms were as unusual and striking as I’d hoped. This spring it wasn’t showing any sign of leafing out, though. I was afraid it had died for lack of an insulating snow blanket during our strange winter. But now a few leaf buds are opening, giving me hope that it just needs more time. 

Carolina allspice in bloom

Not dead, starting to break dormancy

     






Some plants leaf out so late that I have to remind myself not to despair. Is this an evolutionary strategy? It may just reflect their origin farther south than New England. I’ve noticed this with oakleaf hydrangea (Hydrangea quercifolia) too. A new one I planted in front of the house is just starting to show signs of life. 

 
*  *  *
A follow-up to last week’s post: The daffodils did bounce back when the snow melted. You can’t keep a good Narcissus down!

Ice water in their veins

Years ago we replaced our front lawn with vinca (Vinca minor, also called periwinkle). That means I can plant spring bulbs under the evergreen leaves of the groundcover, something I couldn't do with the former grass lawn. 

     This winter’s changeable weather, with scarce snow and intermittent warm temperatures reportedly caused by El Niño, has given me an opportunity to admire the resilience of daffodils.

    One result of a warm February and March has been early emergence of spring blooms. For the past several weeks now the vinca has been sporting its five-petaled violet blue flowers. The bulbs I’ve planted have sent up their first sprouts between the vinca leaves, and flowers have opened in their sequence:

Snow crocuses (Crocus tommasinianus)

 

Snowdrops (Galanthus nivalis)

 

Glory-of-the-snow (Chionodoxa forbesii) 

Spring crocus (Crocus vernus)

  


This week the first daffodils bloomed:

Narcissus 'Jack Snipe'

 This weekend wet snow temporarily covered the flowers in the front yard. You’d think this treatment would spoil the blooms, but it doesn’t.

    Daffodils originated around the western Mediterranean and in North Africa, where they grew in much dryer, sunnier conditions than they find in my New England yard. They’ve succeeded adapting to life all over the temperate zone of the Northern Hemisphere, spread around since ancient times by the Greeks, Romans, and Ottoman Turks, to as far as China.

    European settlers brought daffodils to North America early on. They’re true perennials, living and reproducing indefinitely in places like the Ukraine, where 643 acres of daffodils bloom in the Narcissi Valley of the Carpathian Biosphere Reserve.

Valley of Narcissi near Hust, Ukraine

    The daffodils in my front yard are showed no sign of damage after the weekend's snow. I learn from Linda Chalker-Scott that when cold kills new leaves and buds, they’re dying not from ice damage but from dehydration. Ice forming in spaces between cells draws water out of the cells, which can dry them out fatally. Apparently it takes more than a few hours of snow with temperatures in the thirties for this process to affect daffodils.
    
The wet snow did weigh the stems down. The daffodil blooms were lying on the ground in the morning. 


By afternoon as the snow melted, they started to straighten back up. Monday more snow fell. We'll see if they're still pretty when it melts. My money's on them.

      Unfortunately what does limit the daffodils' flowering in my front yard is lack of sun. The bed faces east and is shaded both by the house and by street trees, when they leaf out. The plants keep sending up leaves, but they can’t store up enough energy during the summers to bloom after the first year or two. 

That’s OK with me. It’s worthwhile to plant new daffodil bulbs every fall in order to enjoy the spring show.