The horticulture of Hydrangeas

One of the best plants for your yard or flower garden is the lovable mophead hydrangea (Hydrangea macrophylla). Mopheads have flower clusters which are large and rounded. Here are a few reasons why they are such good choices:

1. The blooms are some of the most beautiful around, and they persist over a long season.

2. If you accidentally prune away the new flower buds, some varieties will set a new crop by fall.

3. If you forget to prune or refuse to do it, never fear-you really don’t have to worry with it. (However, if you do prune, you’ll get more and bigger flower heads).

4. If you accidentally plant them in the wrong place, they don’t mind being moved.

5. Humidity, which harms many plants, is actually good for hydrangeas, keeping them hydrated and reducing the impact of sunlight on the leaves.  

6. They love water, thriving along creeks, near the ocean, and in heavy, moist soils.

7. While they need water, they will survive most droughts. 

8. They are fast growers.

9. They live for a long time (50 years or more).

10. Deer and rabbits leave them alone (the buds contain a cyanide derivative).

Hydrangeas are woodland shrubs, thriving in filtered shade in the wild. Make sure, if you are planting some, that they are protected from the strongest sunlight of the day. Dig the planting hole about twice as wide and deep as the root ball of the hydrangea. Then set the plant in the hole so that the crown (the place where the stem meets the soil) is just above ground level. 

Fertilize your hydrangea at planting time and again in early summer. Feed them twice annually thereafter also, once when the new growth is beginning in the spring and again in late spring or early summer.

Snails and slugs can be a pest of very young hydrangeas. Older plants don’t seem to be bothered by them for some reason. A shallow dish of beer nearby seems to attract dozens of slugs overnight-just make sure that the rim of the dish is right at ground level and not too high. Hydrangeas have few pests once they get past their first year. 

Remember that a hydrangea’s flower color depends on the pH of the soil in which it is planted. Give it an acidic or low pH soil and the blooms are bright blue. Give it an alkaline or high pH soil and they are pink.

A very exciting development in hydrangea culture is the ‘Endless Summer’ variety. Developed in Minnesota, it blooms on old and new wood. This means that here in the South we stand to get two huge flushes of flowers-one in early summer and the other in the fall, with lots of blooms in between. Endless Summer reaches 3 to 5 feet tall and 3 to 4 feet wide, making it just the right size for a foundation planting (hydrangeas love being planted near the wall of the house because it gives them extra warmth plus protection from the wind), low hedge, accent planting, or middle to rear shrub border. It tolerates heat and high humidity, yet withstands cold winters, freezing rains, and even drought. Once established, it is very low maintenance, requiring only a yearly pruning to encourage big and plentiful flowers and a feeding twice per year.

Plant some hydrangeas this year and especially some Endless Summers!

Tim Lewis is a Georgia Green Industry Association Certified Plant Professional, gardening writer, and former Perry High School horticulture instructor. He can be reached at (478)954-1507 or timlewis1@windstream.net.