Growing Hydrangeas
Hydrangeas: The Classic Garden Plant
These flowering deciduous shrubs are easy to grow and long-lived with some simple hydrangea care and feeding. There are many cultivars, offering a wide variety of stunning colors, styles, and sizes. Below is some straightforward advice for successful growing and long-lasting results.
Hydrangea Care and Feeding
When you are choosing a hydrangea cultivar, check the tag on each plant for detailed information such as sun requirements and growth height and width. Putting the right plant in the right place will make your garden easy to take care of year round.
Site & Soil:
How much light will the plant receive? Will your hydrangea do best in shade or sun? With some exceptions, most prefer protection from hot afternoon sun.
In preparing for the soil, dig a hole twice as wide and only as deep as the container your plant came in. All hydrangeas prefer compost rich, well-drained soil.
Planting:
In a new planting bed it's best to amend the entire area (by one third) with compost. If preparing an individual hole, replace the same soil back into the hole and mulch the top with compost, being careful not to bury the trunk of the plant.
Fertilizing:
A yearly addition of compost may be all that is necessary in the first few years. Mature plants will benefit from an all-purpose organic fertilizer. Apply twice yearly, in early spring and again after flowering.
Pests + Diseases:
Hydrangeas are remarkably disease and insect-free - and a little hydrangea care and feeding goes a long way in strengthening your plant's defenses. Powdery mildew is a fungus that can appear on leaves, but allowing for good air circulation around the plants helps control this.
Flower Color:
The soil in the Pacific Northwest is mostly acidic, so most big-leaf and mountain hydrangeas tend to be shades of blue. To raise the pH for pink flowers add potassium nitrate well before the flower heads have formed. To lower the pH for blue flowers apply aluminum sulfate.
Flower color is affected by the relative availability of aluminum in the soil. Acid soils (pH 5.0-6.9) produce blue flowers; alkaline soils (pH 6.0-7.0) produce pink to reddish flowers. When the soil's pH is above 7.0 the leaves of the hydrangea can begin to yellow. In general, some specific cultivars and white flowers are not affected by pH.
Try these knockout combinations:
- 'Endless Summer' Hydrangea AND Golden Japanese Forest Grass (Hakonechloa macra 'All Gold')
- 'Glowing Embers' Hydrangea AND Concorde Barberry (Berberis thunbergii 'Concorde')
- 'Limelight' Hydrangea AND Painted Fern (Athyrium nipponicum 'Pictum')
- 'Pia' Hydrangea AND 'Hadspen Blue' Hosta
Hydrangea Types + Pruning Techniques
Pruning Technique #1
Prune off last season's flower heads to the first bud or pair of buds beneath the flower heads. However, with established plants cut back about 1/3 to 1/4 of the oldest flowered shoots to the base. As a result, this will promote new growth to the base.
Pruning Technique #2
Cut down to approximately one-two feet. Some thinning is useful to create sturdier stems to support this plant's large flowers. This method may also be used to rejuvenate old shrubs, and should be done annually in early to mid spring.
Pruning Technique #3
For vigorous climbers flowering on old growth; no regular pruning is required. Firstly, prune to fit available space, or as needed after flowering. Secondly, thin for light and air on mature plants
Still have pruning questions?
Plant Amnesty, a local Pacific Northwest garden group specializing in pruning, has some down-to-earth pruning video demonstrations. Here's one about hydrangeas.
In conclusion, with a little hydrangea care and feeding, success is easy. Happy Growing!
