Commentary: There's a secret formula for selecting hydrangeas
FARGO — Remember back in high school when students would whine to the teacher, "Why do we have to memorize this? We're never going to use it in real life."
I've got to admit I've rarely used the quadratic formula and I've survived without factoring equations for nearly half a century since. But some memorization in high school and college actually pays off, such as learning botanical names of plants.
Anyone who enjoys their yard and garden will never regret being familiar with official Latinized worldwide botanical names that unlock the key to plants' vital statistics. And sometimes, it can save a whole lot of plant heartache.
Take hydrangeas, for example. Plant breeders have developed exciting new types during the past decade, making hydrangea one of the most popular flowering landscape plants. But some types don't grow well in large portions of North Dakota and Minnesota, while others do.
Garden centers sell Endless Summer, Twist 'n Shout, Annabelle, Incrediball, Vanilla Strawberry, Bloomstruck, Quickfire and dozens more. Among this list are great varieties mingled with others that struggle greatly. How do we separate the wheat from the chaff?
Luckily, there's an easy way to quickly separate beautiful, adapted hydrangeas from those that struggle in our climate — and you guessed it, it's by examining their botanical name. A plant's botanical species is its unique worldwide identification, like its Social Security number.
The botanical name is often inconspicuous on a plant tag, hidden somewhere below the prominent brand or marketing name of the plant. The name has several parts: Hydrangea is the genus name, followed by the species and a cultivar, or variety name. The species is the key to separating adapted from non-adapted. For example, if a plant tag reads "Hydrangea arborescens 'Annabelle,'" we recognize it as regionally adapted.
Most of the hydrangeas sold in our region can be divided into three Hydrangea species. Hydrangea arborescens and Hydrangea paniculata varieties are well-adapted, while Hydrangea macrophylla varieties are difficult.
• Hydrangea arborescens varieties: Included are the most common hydrangeas with their huge, round, white flower clusters. Popular cultivars include Annabelle, Incrediball and Invincibelle Spirit. Arborescens types are all well-suited to our region and especially valuable for north and east exposures in our landscapes, including shade.
• Hydrangea paniculata varieties: These are easily recognized by their pyramid-shaped flower clusters, called panicles, from which the species name derives. Varieties include PeeGee, Vanilla Strawberry, Quickfire, Little Lime, Little Lamb, Pink Diamond, Strawberry Sundae and many more. Paniculata types are regionally well-adapted and bloom best with sufficient sun, rather than dense shade. All hydrangeas prefer soil amended with organic material and kept moist with a generous layer of wood product mulch.
• Hydrangea macrophylla varieties: More closely related to the florist hydrangea, these types have been highly marketed in the Upper Midwest but struggle greatly in large portions of North Dakota and Minnesota. Included are the easily recognized Endless Summer (original blue), Blushing Bride Endless Summer, Twist 'n Shout Endless Summer and Bloomstruck Endless Summer.
In a previous column, I extensively polled gardeners to solicit their experience with Endless Summer Hydrangea types, and most gardeners met with failure after the first season. A small minority were successful in a sheltered, shaded location, kept very moist, mulched with shredded wood and given protection over winter.
Difficulties experienced by homeowners with Hydrangea macrophylla varieties reinforces past recommendations by horticulturists that the species is not well-suited to our soil and weather conditions.
So, Hydrangea arborescens and Hydrangea paniculata varieties perform wonderfully in our region's landscapes. Hydrangea macrophylla varieties are not as well-suited and require special care that prevents widespread recommendation. Check the botanical name on the plant tag, focusing on the species name.