Hydrangeas are among the most popular garden plants. They’re found in landscaping and ornamental gardens around the world due to their striking spherical flower heads which, depending on varietal and soil conditions, may come in a lovely array of colors. Pinks, purples, blues, and ivory shades are all common, and under the right circumstances the flowers may last for months. Fast growing, beautiful, and just plan fun, hydrangeas are a great perennial addition to many garden spaces so let’s dig in and learn a bit more about them!
A quick note before we begin. Hydrangeas may be harmful to both animals and humans if ingested. If you, someone else, or one of your animals/pets have done so, please contact poison control, a medical professional or seek emergency care.
The Basics of Hydrangeas
While we tend to talk about them as a single entity, hydrangeas are actually a broad family of plants which are collectively native to Asia and North America. What’s especially interesting about the hydrangea family is the variety of shapes they take: while most are small shrubs and bushes between 3 and 10 feet/1 and 3 meters in height, some others are trees or even large woody vines! This variety is part of their popularity; there’s almost certainly a hydrangea that’s right for your garden.
The most popular species of hydrangea in home gardens is by far Hydrangea macrophylla. The name “macrophylla” means “having large or long leaves”. It’s also known as “bigleaf hydrangea” or “hortensia”. This varietal can grow up to 10 feet/3 meters tall and 8-10 feet/2-3 meters wide, but it responds well to pruning and can be shaped fairly easily with a little practice. Other popular varietals include H. paniculata and H. arborescens. You may want to ask around and see which kind of hydrangea grows best in your area—given their popularity your local nursery or garden supply store will likely know.
Many hydrangea varietals display an interesting trait: flower color depends on soil chemistry. In alkaline soils, the flowers will be white. In acidic soils, they’ll turn blue or purple. Some varietals of hydrangea also display red or pink flowers in more neutral soils.
Caring for Hydrangeas
In further good news, hydrangeas are fairly easy to care for. As with all plants in all gardens, choosing the right planting site for your new hydrangea is an important first step. Hydrangea in general like shade to partial shade, although sun-friendly varietals do exist. More sun or warmer conditions will mean that the plant requires more frequent watering in order to thrive, however, so please take that into account as well.
Hydrangeas generally prefer well drained soil that’s rich in organic matter. We absolutely recommend good compost as a soil amendment for hydrangea—it helps keep the soil from getting too dense without adding too much nitrogen. Soil that’s too rich in nitrogen can lead to plenty of green growth but few flowers, and while a bloomless hydrangea is pretty enough on its own the flowers are the real show-stopper with this plant. Good drainage is important; if the roots get too wet the leaves may start drooping or turning brown. Hydrangeas like lots of water but they also require good drainage, so keep an eye on your soil and amend it as needed.
Fertilizing hydrangeas is a contentious issue among hydrangea enthusiasts. This is one of those moments in gardening when everyone has their own system that works for them and they’re quick to defend it! We find it best to use a balanced fertilizer a few times a year, generally in early spring, early fall, and during the peak of bloom season. Yellowing leaves on a hydrangea are a sign that it may need a dose of fast-acting fertilizer. As always we recommend using all natural organic fertilizers when possible.
We mentioned earlier that the color of hydrangea blossoms depends on the soil pH, so having hydrangeas can be an excuse to experiment with soil chemistry. Just remember that rapid changes in soil pH can be hard on a plant, so adjust gradually for long-term results. Coffee grounds are a great natural soil amendment for increasing acidity, while garden lime or garden phosphate can make things more alkaline.
Pruning is best done in the spring, as hydrangeas mostly bloom on old growth parts of the plant. Pruning in fall is safe but it will mean fewer flowers when the warm weather returns. Prune hydrangeas with a sharp clean pair of strong garden shears, cutting at a 45 degree angle about an inch/2.5 centimeters above a budding node. The buds become flowers, so you’ll want to keep those on your plant.
Hydrangeas are a joy, and we can see why they become a hobby if not an obsession for some gardeners. We hope you’ll consider giving them a try, and that this blog has at least increased your understanding and appreciation of these lovely garden plants!
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