Archives for August 2010

Some Thoughts on Spacing

Once there is a landscape plan in place, there is the matter of the plant count.  Determining a plant count has much to do with spacing.  I have read much about rules for spacing plants properly for optimal growth, but the issue is more complex than that.  For instance, if I am planting pachysandra, and space them at a foot apart, I need one plant per square foot.  For 500 square feet, I will need 500 plants, or about 10 48 count flats.  If I space them at 6″ apart, I need 4 plants per square foot, or 2000 plants, or about 40 48 count flats.  Option A asks for a modest up front investment, but I see a lot of time ahead devoted to weeding, the purchase and spreading of a lot of mulch, and a lot of water thrown on bare ground.  I also see a grim looking space for probably 3 years.  My solution?  Start a groundcover bed small and plant densely.   Enlarge it next year, or the following season- only that number of square feet you can plant densely.  My mature, healthy beds of pachysandra-individual plants are much less than an inch apart.

Spacing evergreens has everything to do with the desired outcome.  Should I plant a taxus densiformis in the middle of the lawn, and give it 50 years to grow, I will have a single plant of considerable size.  A hedge, or a mass of yews is more about a community. Sometimes I look at the distance between the rootballs.  The big idea here-everybody has their own subterranean digs. This may mean that the foliage touches.   

Plants are much more sociable than I.  I want my space. I was never so conscious of the need for my own space than after my knee replacement.  I was less than stable on my feet, and was not interested in an enthusiastic Golden Retriever broaching my borders. But plenty of plants do well planted in close quarters.  They are completely happy to relinquish their individuality, and become a part of a larger community.

One of my most favorite landscape moments-the arrival of the plants.  These 1.5″ caliper fastigiate hornbeams in 25 gallon pots would be planted as if they were the poles of a pergola. Carpinus betulus “Frans Fontaine” is a culitvar of fastigiate hornbeam which is slower and more densely growing than the species.  Even so, it will grow 30′-35′ tall, and 15′-18′ wide. I spaced them at 8′ on center, knowing they would grow together.  Someday there would be a green roof under which there would be shade.   

I had other reasons which influenced my spacing.  The house next door loomed over this side yard property.  Evergreens would have provided year round screening, but they occupy a lot of space at the ground plane.  My clients wanted to entertain in this space.  Given enough time, and spaced close together, they would eliminate this view of the neighbor.   

Carpinus are also very tolerant of pruning.  Decisions about spacing are specific to the species in question.  The vast majority of green spaces have not been planted by a person.  There are those wild places densely populated by plants.  No natural forest or meadow is at equilibrium; some plants are coming on as others are in eclipse.  Perhaps a lighting strike will “prune” a giant tree such that new plants can take hold around it.  Should you be interested in the exceptions to any gardening rule, visit any wild and untended space. 

Five years later, the new yews have grown together to make a mass.  The topmost row of yews had been transplanted from the front of the house; the new yews will eventually cover their bare lower limbs.  It sometimes makes more sense to underplant an old and ungainly shrub rather than tear it out.  These big old yews will eventually become part of a simple mass.Eight years later, the house next door has all but disappeared. As the carpinus grow taller, they can be selectively pruned on the underside to permit easy passage beneath them. 

The yews planted behind the carpinus are planted on a gentle slope that rises to the neighboring driveway. Though the shade has become considerable, they are green and well needled from top to bottom.  Allowing those densiformis yews to keep their natural shape is in large part responsible for their continuing health.  Yews do not respond so well to hard formal pruning.  Once all light is blocked to the interior of the shrub by a proliferation of growth on the exterior, those inner branches will go bare.  I have begun planting Taxus media Moonii in place of Hicks yews, as their natural growth is much more upright and formal. 

This is a great spot to sit.

Green And Good Looking

Our temperatures have gone back into the 90’s, topped with a big dollop of high humidity;  I am seeing signs of summer’s end in a lot of container plantings-including my own.  Crispy stems, mildew, and all manner of other trouble one can put under the heading of late summer malaise. Green plantings seem to keep their good looks, even when the late summer doldrums look more and more like the beginning of the end. To follow are some of my favorites this year.

Lime licorice, white polka dot, and a dracaena whose name I do not know-what a fresh look for August 30.

Lemon grass, variously underplanted with basil, parsley, and strawberries. 

King Tut, lime nocotiana, variegated licorice and cream petunias

Australian tree ferns, bromeliads, boxwood, pachysandra

Agave, datura metel

Eugenia topiary, parsley

datura metel, nicotiana mutabilis, gardenia standard, cirrus dusty miller, lime licorice

variegated ivy on standard, boxwood standard

Rosemary on standard, strawberries, fiber optic grass.  It is amazing how beautiful a collection of green plants can be, whatever the weather.

At A Glance: The Venus Dogwood

I was  fortunate to hear recently from Wolfgang Eberts in Germany; he apparently read my previous posts on the Venus Dogwood.  He tells me that this fabulous dogwood has proved to be very popular in Europe.  He accompanied Elwin Orton, the hybridizer of Venus, to the Chelsea Flower Show, where it took a well-deserved gold medal.  Wolfgang is a plantsman, and an European distributor of Venus.  His  nursery also sells other fine plants, including bamboo.  What fun to hear from him.  All of the pictures are courtesy of Wolfgang Eberts.

Wolfgang Eberts

from left to right; Wolfgang Eberts, Elwin Orton, hybridizer of Venus from Rutgers University, and Hugh Johnson-taken at Chelsea

trade show display of Wolfgang’s nursery about Venus

trade show booth

detail, Venus flower

fall color

Venus dogwood does not set much fruit here, but when it does, it is spectacular.  For more information on Wolfgang Eberts, try, and  What a pleasure it was for me to hear from him.



Stature is a concept everyone understands. Any human being 6.5 feet tall gets attention-just for being heads and shoulders above the rest of us.  A physical presence makes an unmistakeable impression.  Alan Armitage has made a life’s work of studying plants.  His shoulders-a whole body of work about what plants work, and what plants a gardener might consider passing by.  His head-he writes and speaks intelligently and passionately about that human activity close to those shoulders-gardening.  You may agree or not with him, but he has stature such that any serious gardener would give pause, and consider what he has to say.

Anyone of stature has the power to give pause. That the modern world is geared towards everything running at top speed, anything that slows me down has stature.  True stature has to do with size, persistence, experience, and longevity. Trees do a good job of filling that bill. They are very large plants. I have read that the standing weight of a 26″ diameter hardwood is 4.2 tons; a mature oak tree will have close to a quarter million leaves.  Some trees live a thousand years.  Others grow to towering heights.  Some grow in wild places never having had any care, and endure. 

 This columnar beech is almost 30 feet tall, and has been growing at a tree farm a good many years.  GP Enterprises sells and transplants big trees.  This is a very specialized part of the landscape industry, as the cost of the equipment which which moves those trees safely and successfully is astronomical to buy, operate and maintain.  Not everyone needs a tree of great size, but sometimes the stature they confer on a landscape makes a lot of other work unnecessary.  What a person might spend on shrubs or perennials over the years can come to a lot more than the cost of one large tree.

Any tree has stature potential; small trees are reasonable to purchase and take hold much faster than a specimen sized tree.  That said, the most difficult part of adding young trees to a landscape is the placement.  No one wants the expense of taking down a very large tree planted too close to their house, or their sidewalk.  A properly placed large growing shade tree can look lonely before it grows into its own. These 4 inch caliper Bowhall maples pictured above will eventually tower over the ground plane.  Planted at the corners of a 12 by 12 or 15 by 15 foot space, you will have a maple tent in not so many years.  Plant 8 or 12 trees, a  pergola big enough to entertain in.  You can see the potential for a landscape feature with stature in this picture.

Columnar carpinus has a natural growth habit that reminds me of an egg with a softly rounded top.  Columnar trees do not co-opt all the available sun, and they do a great job of screening out an untoward view.  Maturing at 40 feet tall, and 30 feet wide, they have an elegant form that appeals to me.
This older multi-trunked Amur maple has an entirely different look than the carpinus.  The carpinus I would call architectural, and imposing-the Amur maple is graceful and lovely.  This insouciant amur maple meadow is as visually successful as a formal landscape-just different.  The choice of a tree or trees can influence the atmosphere of a space. 

Ralph Plummer owns GP Enterprises, and though he landscapes, builds retaining walls, engineers drainage and grading, he has made a life’s work of moving and planting big trees. Even if he were not 6′ 6″ tall, he would still be a person of great stature.