Need Help?

Allan designs and plants flowering gardens in Montreal, Zone 5 [USDA Zone 4] .

See website, design work and favorite flowering plants at

Consultation and coaching for do-it-yourselfers is provided. Occasional emailed questions are welcome and answered free of charge. Oui, je parle francais.

See my work on Pinterest at Garden Guru Montreal

Entries in rock garden plants (2)


A Drought-Tolerant Perennial that is Really a Shrub

Image: canbyi is a drought tolerant, cold climate, evergreen plant hardy to USDA Zone 4, perhaps even 3. When I first discovered it, accidentally, in a grab bag collection of perennial seedlings at a behemoth retailer, it seemed appropriate as rock garden ground cover.

Fascinated by its rich, dark green and sensuous pinnate foliage, I placed it in a dry sunny spot, among the Phlox subulata and the Arabica caucasica. That’s how I created a visually effective composition of various low growing foliage plants, that cascaded over the rock garden.

Extreme close up image from wikpedia.orgThroughout the season, Paxistima would stand out from among all of them. To the eye, it appeared prickly, but to the touch, it was soft, smooth, and silky. It beckoned me closer every time I noticed it and I would reach out to stroke it with the same eagerness as petting a puppy. What an exciting and moving tactile experience!

Image: arrowheadalpines.comIt was a surprise to realize how slowly this plant would mature. However, its lack of height [mine grew one inch high but it can reach 12 inches] and its disciplined spread [it will slowly grow to 5 feet wide if left untrimmed, but it is not invasive] were compatible attributes with my gardening personality. I was pleased that it could thrive in dry clay, in a heat-and-drought-ravaged corner of the garden.

After ten years of making me happy, I lost the plant in a renovation project when, for structural reasons, the rock garden had to be demolished. Since Paxistima had insinuated itself between several large boulders and was rooted into hard clay, there was no way the demolition crew could save it.

A few years later, when I began to landscape other people’s gardens, I found a new need for my long lost but loving Paxistima. Providing it is manicured each season, this soft, sensual, and reliable evergreen plant can be used successfully as background filler in the front border of flowerbeds.

However, when I began to hunt for it anew, I discovered two facts that had eluded me. First, in some parts of the country, Paxistima is almost impossible to find at retail. Second, it is not a perennial but a miniature shrub.

Very small shrubs that exhibit attractive sensory attributes have an important role to play in the design and appearance of perennial flowerbeds. There will be more on this subject in my next post where I hope to report on three relatively new miniature shrubs suitable for cold-climate gardening.


Lamium, a Gracious Groundcover Perennial

Lamium Anne GreenawayThe neighbor was being generous. He had just finished manicuring his rock garden and had buckets of extra Lamium to spare. I had just purchased my property and had three, 60 feet long, empty flower borders to landscape. Free perennials were always going to be welcome, or so I thought. Five years later, the free Lamium grew exponentially and every inch of flowerbed that had not been protected with the spreading foliage of other perennials, became a seeding ground for future generations of this now-unwelcome perennial.

I spent the last three years trying to rid my property of my neighbor’s gift. I no longer have a rock garden, where the spreading and anti erosion properties, that Lamium provides, are appreciated. As well, this ground cover has no purpose in my garden. All of the flowerbeds are test gardens for upright perennials. There are no applications, even in my client base, for spreading groundcover.

A while ago, my daughter in Boston e-mailed with an inquiry. Her husband had planted a row of solid color dark green Hosta along the edge of a rock garden that runs the length of a driveway. He left an empty space between the Hosta and the asphalt so that the Hosta might have room to grow. It was his expectation that these plants would spread to cover the border. After five years, they had not done so. They had been mature perennials, transplanted from other parts of his garden; they had done most of their spreading. Any additional growth would now take years. My daughter inquired if I would recommend a rugged and step-able plant to fill up the emptyness and Lamium sprang to mind instantly. I recommended the Anne Greenaway variety because I believed that its green/yellow variegations would appear luminous against the solid dark green foliage of the Hosta.

Recently, a client asked me to fill in a one-foot wide bed that separated a hedge of Spirea Magic Carpet from the walkway. The hedge foliage has a gold cast with pink flowers, and Anne Greenaway, once again, proved to be most appropriate. The yellow of its variegation combined with its pink flowers echoed the color scheme of the Spirea, while the small plug-size of its pot [I found it at a big box store] made it the perfect size to plant in such a small space.

That I recommended Lamium in both cases surprised me because after my experience trying to control and eventually get rid of it, it is no longer a favorite plant. I suppose that I must be an equal opportunity gardener; I recommend the best plant for the job, regardless of any other considerations.

Lamium would be appropriate for a rock garden, while the thick carpet of ground cover that it creates makes it an excellent anti-erosion plant.  Rugged and step able, it grows in damp or dry earth, from full sun to full shade, and needs no attention whatsoever. In spite of its aggressive growth, it is the most luminous of all groundcovers and one of the most floriferous. There are several varieties, each distinguished by its own particular leaf variegation or by the color of its flower. It also has a pleasant fragrance when in bloom. The white, silver, or gold variegation on its leaves are an attractive contrast to the solid green foliage of most other plants.

This is a vigorous but easily controllable spreader. Its roots are never so deep that they defy removal. Lamium is a fertile plant. Not only does it grow exponentially, but it is a prolific self sower. As well, it is easily propagated by planting even rootless stems, some in bloom, into damp earth. Lamium has the growth habit and hardiness of a weed so that even stressed-looking plants that appear to be poor quality, sickly, or even puny, will rejuvenate easily and increase in size in a very short time.