Cultivating your garden: visitors to the plant garden tour have asked questions about…

Thank you to all the gardening enthusiasts who supported the Niagara Falls Garden Walk last week – it was a huge success.

A special thank you to volunteers Dawn and Dale who welcomed some 165 visitors to my garden. It was a pleasure to meet so many of my readers and hear about their gardens.

A few plants caught the eye of many visitors, Tuff Stuff hydrangea, faux indigo and bear panties come to mind, as well as a jet black fruit tomato, aptly nicknamed “Midnight Snack”. I will introduce tomatoes in a future column, but let’s take a closer look at other plants.

Serving as a colorful backdrop for a pair of chartreuse Muskoka chairs (my favorite place to relax on the way), a quartet of Tuff Stuff hydrangeas enjoy the dappled shape of a black gum tree. As a general rule, hydrangeas prefer a sunnier location with more humidity, but true to their name, these Tuff Stuff hydrangeas bloom on their own from early July until the snow flies.

Also known as mountain hydrangea, this plant shares the showy pink or purple flowers of bigleaf hydrangeas, but because it is native to the mountains, it has better cold tolerance. Part of its success is due to the fact that the plant flowers on both old wood (for early blooms) and new wood (for blooms later in the season). Neat wearing (one meter high, one meter wide) means no pruning is needed. In fact, you shouldn’t prune Tuff Stuff hydrangeas other than to remove dead wood and dried flower heads in the spring.

Tuff Stuff hydrangeas prefer moist, well-drained soil. When the weather gets hot and dry, I treat my plants with extra water (daily, when it’s really hot and dry). Afternoon shade is ideal during the summer months. The color of the flowers varies according to the soil. Acidic soils with an abundance of aluminum (a natural soil mineral) produce blue/purple flowers. In alkaline or aluminum-free soils, the flowers will be dark pink.

The Tuff-Stuff hydrangeas in my garden were planted over five years ago, have rarely needed pruning, and put on a beautiful, easy-care show every year. The rabbits leave them alone, the flowers of the lace bonnet attract pollinators. They attracted their fair share of interest on the day of the garden visit; people loved the lace cap flower, the rich color and the fact that they bloomed in the shade.

Despite the fact that false indigo (Baptisia australis) in the half-moon garden had long since finished flowering, the plant attracted more than its share of attention on the day of the garden walk. What was the attraction? Beautiful bluish-green trifoliate leaves and a crop of pale yellow pods (which look like puffy pea pods) on a generous mound-like shrubby plant that stands 1-1.5 meters tall.

Spiers of purple/blue lupin-like flowers, once used as a blue dye, dominate the foliage of false indigo (Baptisia australis) in late spring.

False indigo is native to North America, with purple/blue lupin-like flowers in late spring on spiers up to 30 centimeters high, extending well above the foliage. The flowers give way to seed pods that ripen charcoal black when the weather cools. The dried pods vibrate when shaken, my grandkids had fun finding them and giving them some shade in the fall. The blackened pods open in winter and look interesting above the snow cover.

The name faux indigo refers to the use of the flowers to make a blue dye. The name Baptisia comes from the Greek word baptism meaning ‘dye.’ This perennial plant forms a deep taproot. It takes two or three years for the plant to mature and it does not like to be moved once established. It is very drought resistant once established. It tolerates shallow clay and rocky soils and does best in full sun, but accepts partial shade. An added bonus, the local bunnies don’t give it a second glance.

Notable varieties include Proven Winners’ Decadence series, including ‘Blueberry Sundae’ (vibrant indigo blue), ‘Lemon Meringue’ (yellow), and ‘Vanilla Cream’ (creamy white).

Acanthus mollis, commonly known as bear breeches, grown for its attractive foliage and bold spikes of unusual flowers, was another popular plant on the day of the visit.

Bear's breeches (Acanthus mollis) features architectural spiers of hooded flowers and beautiful, deeply lobed glossy green foliage.

The showy flower spikes include tiny white flowers, each capped with a spiky, purple bract. Architectural spiers rise dramatically (about a meter high) above the mounding, glossy, deeply lobed dark green foliage.

Acanthus leaves were used as decoration by the ancient Greeks and Romans. Acanthus leaves are believed to appear as carved leaves found on Corinthian columns from the 4th century BC. The name acanthus comes from the Greek word ‘akantha‘ meaning spine, referring to the toothed edges of the leaves.

Bear breeches are easy to grow in average, fertile soil with average moisture. They do not like poorly drained soil. They prefer full sun, but accept partial shade. There may be fewer flowers when grown in shade. In my garden, which can be a little dry for their liking, the acanthus mollis sometimes wilts in the hot midday sun, but revives in the afternoon shade. The plants bloom for several weeks, but the flower stalks persist through the summer.

I usually cut the stems in mid-August when they start to look a little scruffy. Acanthus can spread aggressively in soft soils and milder climates, but I’ve had no issues with their care. Seedlings appear from time to time, they can be potted up and shared with a friend. Young plants can be slow to establish, but are worth the wait.