Star Gardener: The Color Purple

Purple works well on a small scale or in a large park-like setting

Purple is the darnedest color. It attracts us like bees to a honeypot. But get it home and it is nearly impossible to find a spot where it fits in. 

After spending entirely too much time on this conundrum I’m coming to the conclusion that purple works well on a small scale or in a large park-like setting. But not in the smaller domestic properties in which most of us live and garden.

The source of this soul-searching is a glorious 25-year-old purple-leaved redbud, Cercis canadensis Forest Pansy. For 24 years of its life in my garden a smattering of purple foliage peeked out from behind a large oak covered with a dramatic climbing hydrangea. It was charming.

The oak departed last winter. Now Forest Pansy is front-and-center, flourishing and ravishing in the additional sunlight. And I am growing to loathe it. If this keeps up much longer, I fear the chain saw will be called in.

The problem is that even though it is surrounded by green trees and shrubs in a variety of textures and flowers, and flowering shrubs are nearby, nothing can compete with it or subdue it. The impact of the purple foliage is so overpowering that it blinds you to the overall garden and everything else within your line of sight.

Transplant it to the sunny edge of a woodland on a slope extending for acres (and yes, there is such a spot in Georgica), bisected with a wide grassy strolling path, and Forest Pansy would have found its perfect home. This is how redbuds grow in nature, and the novelty of purple foliage would be a good visual diversion. It’s all a matter of scale.

In similar fashion, purple-beech trees meld into the landscape of sunny park-like expanses. Plant them in smaller, more constricted settings, and they appear gloomy and funereal.

Short of removing it, we will prune it this coming winter when it is dormant. Will this work? Only time will tell.

But the allure of purple foliage continues to seduce. Most gardeners say, I once grew Forest Pansy, but it died. Mine seems almost like an aberration.  However, a new cultivar, Merlot, has been introduced recently that is said to be more robust. If anyone is growing it here, I would love to see it and hear how it is doing. A better choice for the domestic garden, probably, would be Ruby Falls, a weeping, compact redbud. This would easily fit into a mixed border of shrubs and perennials. Better yet, it would make an excellent focal point planted as a pair at the top of a staircase or entrance to a garden.

A new Styrax japonicus with purple leaves is just entering the U.S. market, and I for one have lined up to buy it. If it is like Forest Pansy and outgrows its space in another 25 years, I won’t be around to decide what to do.  In the meantime, there will be years of pleasure from it.

I was mesmerized by one in Normandy several years ago and have not been able to erase its image from my head. Yes, the garden was very large, the grassy paths wide and long, so Styrax japonicus Purple Dress attracted attention but wasn’t overwhelming.

Before Purple Dress made its introduction here, an even better form out of the Netherlands began attracting attention. It’s called Evening Light. The first crop is about ready for sale at Broken Arrow Nursery in Hamden, Conn., and small plants are listed by Gossler Farms in Oregon and Wayside Gardens. All are mail-order nurseries.

Purchasing the best form of a plant always pays dividends, but is even more important when flamboyant dark red or purple foliage is involved. Drive around and Japanese red maples and purple plums, Prunus cerasifera, are everywhere; it is the rare one that doesn’t make you grind your teeth in distress. But the maples are probably grown from seed, and the color has been degraded. The plums are a ragtag lot, mildewed, diseased, and sickly looking.

If you are looking for a Japanese red maple in local garden centers, take a critical eye with you. The time to look is June, when the foliage is fresh and most vivid. As the season advances the color may fade and look tired. I prefer to buy Japanese maples from specialist mail-order growers who propagate from good quality stock plants.    

Nothing is more elegant than a good form of Japanese maple, but a possible alternative is the elderberry, Sambucus nigra Black Lace. It has finely dissected leaves in dark purple-black that are said to maintain their color over a long season.

Other shrubs with good purple foliage that work well in borders are the smoketree and native ninebark. The smoketree (Cotinus coggygria) cultivars Velvet Cloak and Royal Purple have almost black leaves through most of the summer when given full sun, and are a spectacular rich red-purple in autumn. The ninebark, Physocarpus opulifolius Diablo, also has red-purple leaves in full sun. Both can be pruned nearly to the ground to promote vivid new growth.

A good shade tree that created a lot of buzz in Europe is the katsura, Cercidiphyllum japonicum Red Fox. It has heart-shaped leaves somewhat like those of redbuds and is columnar, rather than spreading. Its leaves are a more intense purple when grown in full sun, although they gradually fade to bluish-green by midsummer. A specimen of Red Fox is growing at LongHouse Reserve along Peggy’s Path.

The Japanese barberry, Berberis thunbergii Concorde, is a treasure and a keeper. The leaves are nearly black, with ruby highlights when backlit by the sun. My mature plant, on the north-facing side of the house where it receives limited sun, is just under 18 inches high and 3 feet across. At most it gets an occasional snip here and there to keep the compact mound perfectly shaped. What’s almost better is the deer have ignored it, while most of its companion plants must be protected by netting.

In contrast, I recently ripped out Bagatelle, another compact and highly recommended barberry, which didn’t begin to hold up in comparison.

Concorde would respond to shearing to be used as a low hedge or an element in a knot garden.

It is the rare gardener who does not succumb to impulse purchases, and plants with purple foliage are probably at or near the top of the list. So relax and enjoy them. Part of the pleasure is finding the right location and companion plants. And then there is always the chainsaw.