Everyone loves Hydrangeas

By Melanie Mathieson
Gardening Guru

Hydrangeas are widely known and admired for their large, showy blossoms that lend fabulous color to gardens from mid- to late-summer. Hydrangeas are native to both Japan and Korea, but many varieties have been naturalized to be planted in compatible climates around the world. The luxuriant dark green foliage of hydrangeas, offers a striking background to the large round or smooth blossoms. All hydrangeas are deciduous, and it's a sure sign of spring when their tender green leaves begin to appear. Hydrangeas are spectacular grown as single specimens in a perennial bed, but are also fabulous when planted as shrub borders.

Before you get the urge to dash out and buy the first hydrangea that meets your eye, it is wise to learn the difference between the types of varieties that are available, "mopheads" and "lacecaps." Chances are some gardener’s have never heard these terms associated with hydrangeas before. As peculiar as these names sound, they relate to the appearance of the flowers on the plant and are the names designated to the two cultivar groups of “Macrophylla” hydrangeas. Hydrangeas are such a showy plant, it is unfortunate that only a few varieties will grow and survive in our zone, but because of the limited varieties available for our area, it is much easier to tell the difference between the two types of hydrangeas.

Mopheads are also known as bigleaf or garden hydrangeas and are very popular and widely grown. Mopheads feature large round flowerheads resembling pom-poms and bloom from mid- to late summer. Their flower clusters differ from lacecaps in that some varieties produce sterile flowers with petal-like sepals, while others bear smaller fertile flowers with starry petals. Those bearing sterile flowers bloom for several months, although their color gradually fades toward summer's end. Mopheads bloom in solid masses, their clusters often so heavy that they cause their stems to droop and bend. The most common mophead we see in our region is the Hydrangea arborescens “Annabelle”. This variety is easy to identify as it develops the large white pom-pom like flowers, often over ten inches in diameter, in late summer. Sometimes after a light frost the flower petals will develop a slight blush of pink. These flowers are great for drying. “Annabelle” hydrangeas also make a great hedge when planted in rows of multiple plants. Many gardeners do not think to use them in their landscape this way but imagine a hedge full of the large white flowers. Annabelle’s have to be cut back each fall to the ground to promote new growth for the next season.
Another favourite of the mopheads that grows well in our region is the “Paniculata” or “Pee Gee” hydrangea which has eight inch long white flower heads that have a tendency to flop downwards from the branches. This hydrangea gets its nickname from its botanical name, H. paniculata 'Grandiflora' (P.G.). The Pee Gee hydrangea is a shrub that takes on a tree-like form and in some areas it can reach twenty feet tall. The name "paniculata" comes from the fact that the blooms are usually panicle-shaped (somewhat cone shaped) rather than ball or pom-pom shaped. These blooms develop a lovely pink shade as the blooms age, extending their beauty well into the fall. After heavy frosts the petals of the flowers turn a rusty brown. The “Pee Gee” blooms on new wood so if any pruning is required it is best to prune the shrub in the fall. Remember that this is an upright shrub with a defined trunk so you do not prune it back to the ground like the “Annabelle” variety. If after the winter you see some dead branches, it is okay to trim these away in the spring as this will ensure continued good form and vigour.
Lacecap hydrangeas is the other variety of hydrangeas that has some cultivars that will grow in this region. Lacecap hydrangeas bear flat round flowerheads with centers of fertile flowers surrounded by outer rings of sterile flowers. Their center flowers are not exactly showy, however thee outer rings of their sterile flowers are quite striking. Interestingly, the structure of these flowers really does remind one of a fancy "lace cap!" The fascinating flowerheads of lacecap hydrangeas are also somewhat reminiscent of pinwheels. The flowers tend to be light and airy with a delicate structure, not the dense flower structure of the mopheads. There are a few varieties of lacecaps available in our region that will survive our winters and the local nurseries are making them available to us.
Unlike many other species of hydrangeas, that are not hardy in our zone, neither of these types of hydrangeas’ flower colour is affected by the pH of the soil it is growing in. Regardless of the soil type these varieties will bloom with white flowers which turn colour based on the seasonal weather not the soil pH.
Now that you agree everyone loves hydrangeas you will want to add a variety or two to your garden. Just make sure that before you purchase a plant that you check the tags before buying to make sure you purchase one for our zone and you are getting the variety that you want, either a lacecap or a mophead. Some gardener’s recommend making your hydrangea purchase once the shrubs start to bloom in the nursery just to be sure of what you are getting. I advise that you should do a little homework and find the variety that you want to grow, then visit your local nursery. If the variety you want is not a regular item or is new on the market you might want to visit the local nursery in late winter to discuss whether the nursery can add this into their annual tree and shrub order. Planning ahead and doing some research will reward you with best results.