Archives for June 2019

Cornus Kousa

From the Missouri Botanical Garden website, read the following about the kousa dogwood. “Cornus kousa, commonly called Kousa dogwood, is a small, deciduous flowering tree or multi-stemmed shrub that typically grows 15-30’ tall, with a vase-shaped habit in the early years but eventually maturing to a more rounded form. Bloom occurs in late spring. The showy parts of the Kousa dogwood “flower” (3-5” across) are the four narrowly pointed petal-like white bracts which surround the center cluster of insignificant, yellowish-green, true flowers. Flowers are followed by berry-like fruits (to 1” diameter) which mature to a pinkish red in summer and persist into fall. Fruits are technically edible, but are usually left for the birds. Oval, pointed leaves (to 4” long) are dark green, but usually turns attractive shades of reddish-purple to scarlet in autumn. Mottled, exfoliating, tan and gray bark on mature trees is attractive in winter.

This matter of fact description does not begin to address the beauty of a kousa dogwood in full and glorious bloom. I doubt I have ever written about them in the 10 years I have been publishing my garden design journal. Primarily as I have never ever seen them so spectacular in flower as they are right now. The kousa dogwood is native to Japan, Korea, China, and Taiwan. They are rated as hardy and thriving in zone 5 to 8, but my experience suggests they can act a little hostile towards our baking summers, and heavy clay based soil. They seem to favor thin compost rich soil on the acid side that drains in a twinkling of an eye. I do find they perform better than American dogwood (cornus florida) in general.

My theory seems to have some support. This has been the rainiest and coolest spring I can ever remember. We have had many more rainy than dry days. It was 48 degrees this morning, and barely 60 degrees this afternoon. The ground is completely drenched. I make an effort to stay out of the garden, even if it means the foot tall weeds are getting closer to 2 feet tall. The grass is squishy. For the Kousas to put on such a rare show of extravagant bloom says there is definitely something in the air that they like.

The actual flowers are small and insignificant. All of the show comes from the four stiff bright white bracts that surround the flower. In a stellar year, those thousands of bracts overlap one another to produce a solid sheet of white. Even at maturity, a kousa dogwood is small enough to comfortably place in an urban landscape. Sited with some afternoon shade, a routine source of water and great drainage, all a gardener has to do is wait for that one year when all the stars align for a super bloom.

Should you be one of those people who drives the neighborhood to look at holiday lights, a cruise might be in order. You can spot them for at least a block away. Out of flower, they have handsome foliage, and even more handsome exfoliating bark when they are older-but the star of the once in a blue moon show are the flowers.

In 2009, a hybrid of Cornus Kousa, and the Pacific coast dogwood, Cornus Nutallii, was introduced from the breeding program at Rutgers University. Again, from the Missouri Botanical Garden website: the dogwood “Venus” These four trees planted in the tree lawn at my house are young, but they will grow. Even at a 2″ caliper size, I can spot the flowers from several blocks away.

This hybrid is hardier than either parent. They thrive in full sun, and grow fast when they are happy. The flowers can easily reach 6″ to 7″ in diameter. We have probably planted better than 100 of them since 2011, with only a few losses. They are a little shy to bloom until they have been in the ground for a year or two, but once they start, they are stop you dead in your tracks gorgeous.

They rival the magnolias for the showiest spring flowering tree. As with Cornus Kousa, Venus flowers in June, avoiding late spring frosts that so often damage the flowers of magnolias.

A pair of small trees I planted 3 years ago are covered with flowers this year.
This shade garden planted some 4 years ago for my clients features a pair of Venus dogwoods. They are especially happy to have them this year.

Posted on: June 17, 2019 46 Comments

Filed Under: Landscape Design, Woody Plants, Plants, trees Tagged With: kousa dogwood, "Venus" dogwood, Cornus kousa, Cornus Venus

Recent Work

We have been planting container projects daily, one after another, since May 15. With time outs for cold, and torrential rain. I do not ever remember a season quite like this one. Very cold night temperatures, cloudy skies and relentless rains have been the order of the day. A client remarked that we have had rain for 65 days of our last 90. That is an astonishing statistic. It has meant constant interruptions to our work schedule. Cold nights have meant we are hesitant to put temperature sensitive tropical outdoors. The gray skies mean plants have been slow to come on in the greenhouse.

I explained the situation to one client as a discussion about what constitutes providing a good home for a plant. A home is a warm, friendly and inviting place. Home for tropical plants far away from their native home means we wait for weather and soil temperature that approximates the conditions under which they thrive. Many of my clients for whom I plant begonias, coleus and New Guinea impatiens have had to wait. Who doesn’t hate to wait? My suggestion is that their plants are thriving and growing in storage in a greenhouse. Planted out in their pots in cold weather, they would languish. The temperature this morning June 11 at 5am, 48 degrees.

The cold has not been the only issue. Rain is essential to plant life. I doubt I need discuss that with any of you. Rainy weather working its foggy magic on a landscape is beautiful. A rainy day encourages introspection. Or at the very least a nap. I love the rain in all of its spirited and benign forms. But we have had rain day after day without much respite. This is rain of a different sort. Too much rain foments rot both above and below ground. Too much rain spoils blooms. Too much rain dampens the spirit. We have had all of the aforementioned. The most dramatic signs of distress have come from the mandevilleas. These vining plants like hot weather and dry conditions. They look beautiful in the greenhouse, and poor to middling outdoors. It is tough for plants to settle in and thrive when their medium is watery. And more watery.

All of our rainy days have been attended by clouds. Naturally. Growth in annual plants is directly related to sunny circumstances. This means we have been planting smaller plants than usual, in those moments between the rains, in the cold. Am I worried? Not so much. Warmer and drier weather will come our way sooner or later. All of those container plantings will need some time to grow before the design and intent is clear. I have time for that, in my more rational moments. The day a container is planted is its first day – not its best day. The best days are months ahead.

Postponing a planting can be the best strategy when conditions are hostile. This year’s conditions are obviously hostile. But in general, I do most of this planting in late May and June. May is a spring month in my zone. What looks good are the spring flowering bulbs, the wildflowers, and those shrubs and trees that thrive and bloom in cooler weather. The Venus dogwoods are glorious right now. The geraniums, not so much.

One way to deal with lost time is to plant larger plants. 6″ pots instead of 4″. Hanging baskets in lieu of 6″ or 8″ pots. Growing summer blooming annuals from seed or cuttings is a lengthy process. That is why growers have greenhouses, and grow under glass. Many of the most cutting edge of those houses have very sophisticated lighting and watering devices. If warm weather, reasonable water and sun were not necessary to grow on tropical plants, growers would grow outdoors. That said, every greenhouse where I shop has run out of or are low on plant materials that I customarily use all the way through June.

We have a solid 2 weeks of planting still to go. Just like the weather, we are just getting warmed up.

I would not want to do without container plantings, whatever the weather.

Posted on: June 12, 2019 14 Comments

Filed Under: container planting, Color, Deborah Silver and Co Inc

Planting The Summer Pots

The opportunity to suggest a collection of pots to a client is pleasure indeed. We looked at lots of them, but she kept coming back to these Belgian stoneware pots. This was no surprise, given that the architecture of her house is contemporary. And dramatic. The roof combines a large curved window with strongly angular geometric shapes set in a variety of planes. The overhangs are substantial. A pair of large brick planter boxes and an over scaled walk to the front door contribute even more in the way of hard surfaces. It was a given that my client was interested in multiple pots. They would provide a vehicle for introducing some green to the front entrance. Three pairs of pots, different in size and color, would provide lots of opportunity to soften all of the hard surfaces. It took a while to arrange the pots, but both of us were happy with the outcome. The planting design came next.

The planting design of an associated group of pots takes some thought. They needed to relate to each other in color and feeling. They also needed to be of a scale appropriate to the size of the pots. A pair of lemon cypress almost 5 feet tall would provide strong color and texture on either side of the front door. That color would set the stage for all of the other plantings.

As much as she was interested in contemporary pots, she was likewise interested in contemporary plantings that had a simple and architectural feel. Many of the plants chosen were green plants of various colors and textures. A mix of lime and variegated licorice provided a wide spectrum of shades of green.

To follow are pictures of the planting. Yellow flowered cannas have bold leaves, and the color repeated the lime of the licorice and ginger. A pair of Limelight hydrangea topiaries will bloom a greenish white later in the summer. In the meantime, the spherical shape of the head echoes both the roof windows and the steel spheres.

White petunias and euphorbia Diamond Frost will repeat that hydrangea white on a lower level.

A sudden and strong wind and rainstorm interrupted the effort, but on the upside there was no need to water when we finished planting.

Shrubby plants – both hardy and tropical – are great in large scale pots. The variegated shell ginger, or Alpinia zerumbet “Variegata” features a variety of greens, much like the licorice cultivars. They are a perfect scale for the large Belgian cylinders. In a perfectly hot summer, they will bloom with racemes of white fragrant flowers.

A great planting not only involves a group of people with a respect for plants and transplanting, but a group that understands how to arrange and face them in the pot. Though these containers are a long way from attaining their eventual size and stature, there is no reason why a new planting shouldn’t look beautifully presented.