Brian Minter: Sun loving plants that like the heat

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When people begin to plan and plant their summer containers, baskets and garden displays, one of the most-asked questions is about heat-tolerant plants.

For brilliant, long-lasting summer colour, we need plants that hold up well during periods of intense heat and times of drought. This is especially true for hanging baskets and containers exposed to the sun.

Vines add so much character to baskets, and the colourful foliage of sweet potato vines (ipomoeas) are the best. Now produced in a wide range of colours and growing habits, they are versatile as cascading plants in both baskets and containers.

In addition to the still popular heart-shaped hot lime variety, I. Margarita, and the frilled, lacy, rich black foliage of I. Blackie, new varieties are available from all over the colour spectrum. Two Proven Winners series, Sweet Caroline and Illusion, are far more compact. In the Illusion series, Garnet Lace is bronze, Midnight Lace is a deep black, and Emerald Lace is a frilly hot lime. The Sweet Carolines, with their more traditional maple leaf shape, have a shorter growing habit. Sweet Caroline Light Green is a vibrant lime, Red Hawk is a deep bronze, and Raven is a dark black.

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Silver is certainly an excellent accent colour, and no other silver plant matches the shine of Dichondra Silver Falls, with its small, round silvery leaves on long, fast-growing vines that sway gently in the slightest breeze. I’ve even seen growers create baskets using just these vines.

As one of the most resilient vines, once acclimatized, ivy does great in full sun. The many new variegated forms complement other colours nicely. Indeed, ivies can make a beautiful basket all by themselves.

As for flowering vines, the true sleeper is scaevola, a native of Australia. I remember when it was first introduced 20 years ago. We were carrying a supply of them at our garden centre, but they were not selling. So, we planted them in our gardens on a hot, sun-scorched, west-facing bank. Talk about a stunning display in the worst heat and drought situation. Today, they come in a wide range of colours and length of flowering stems. From pure white and soft pink to shades of blue, they are truly the workhorses of hot summer colour.

A trailing portulaca, called Cupcake, is the new kid on the block. Available in a range of bright colours, these spillover plants are ideal for mixing with other trailing succulents. The only downside is their tendency to close their flowers at night.

The large green leaves of Dragon Wing begonias really are shaped much like a dragon’s wing. These rising stars, particularly the reds and pinks, are popular for a good reason. Once the flowers appear, they simply don’t quit until fall. The warmer and hotter the location, the darker the foliage becomes until it turns a deep bronze that contrasts beautifully with the vibrant pink or red flowers.

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Lantanas have always been valued for their great colour and their heat and drought tolerance, and today, their form and growing habit has been transformed. Proven Winners Luscious series creates a delightful spilling effect. Because of their massive flower displays, I think they are best planted by themselves. Dummen Orange has also developed a nice trailing series in a wide colour range that includes white. Lantanas attract hummingbirds and other pollinators.

When I was in Switzerland a few years ago, virtually every home, business and train station was graced with beautiful, single flowering cascade and mini-cascade geraniums. The cascades are far more vigorous than the compact minis, but they both perform beautifully in full sun. The cascades come in white, pink, red and lavender. When in full bloom, they are a blaze of colour throughout summer until fall. In our part of the world, they haven’t yet caught on (I’m still hoping), and because of this, they can be more difficult to find.

Once acclimatized to the sun, upright geraniums are among the best heat and drought tolerant performers. Zonal geraniums, with their nicely patterned leaves, come in both compact and larger sizes. Another great innovation, the Calliope geranium is the result of crossover breeding between upright and trailing varieties. I love its gentle spill habit while still offering a good upright performance. Today, there are many similar geranium crosses on the market.

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Petunias of all types are still among the most popular sun lovers. Innovative Wave petunias have captured everyone’s attention.  Available in a wide range of colours, they cover ground like no other plants, and they have great weather tolerance. Proven Winners’ line of supertunias and Vista petunias are great used in containers or as ground plants. Bubblegum, quite possibly the most vigorous petunia ever created, explodes with colour like no other. If you love pink and lots of it, this one’s for you!

Today, there are so many plant innovations that it is hard to keep up. The Triploid series of hybrid marigolds is an example of this trend. They don’t produce seed, but they do outperform all others. From the new blue salvias to zinnias, summer rudbeckias, celosias, vincas and pentas, all deliver great performances in hot summer weather.

With so many choices, we can all create glorious displays that will thrive in the summer heat. Bring it on!