Erin Castillo | GYHG and Certified Hydroponic Grower, Gardening Writer
Wednesday, February 16, 2022

For those wondering when to prune hydrangeas in Georgia or in Zone 7, now is a fantastic time to think about these beautiful ornamentals and learn any basic care considerations to act on now for big blooms later in your growing season. Here we will deep dive into how to grow hydrangeas in the South and five care tips to consider.

Location depends on cultivar — Be sure to check your variety’s sun or shade needs before planting. If you messed up, you may want to move it while dormant in cold months

The Hydrangea is a perennial typically in Zones 5-9 (with a few rare varieties that are exceptions and can live in Zones 3-4 with winter protection), but this can greatly differ depending on your cultivar, so be sure to check the growing tag that comes with your plant from your local nursery or Monrovia has put together a good resource page you might want to check out as well.

The location you place your hydrangea also matters in the Southeast. You’ll want to protect your hydrangea plant from the extreme summer intensity of the sun (we don’t call it “Hotlanta” for no reason!) Note: be sure to check your cultivar as some hydrangeas do prefer full sun, part sun, or shade.

Conversely, if your Hydrangea is too exposed to extreme cold winter winds and extreme cold weather temperatures, your plant may not form adequate bud formation. Planting your hydrangea near a structure that retains heat while also offering a wind break (like a brick building or foundation) will help your plant produce the stunning of blooms for display you seek. If your temps reach down towards zero degrees or lower, you will want to carefully wrap your Hydrangea plant with a layer of thick burlap to protect forming buds from cold injury. Take wire fencing the height slightly taller than your hydrangea bush and make a circle around your plant then wrap burlap or a cover designed for protecting plants from frost around your plant. This will protect those forming buds and dramatically affect your plants ability to bloom for the following growing season.

What to Add to Your Soil and When You Should Make Adjustments

Before adjusting anything with your soil, be sure to do a soil test at the same time every year (preferably in the fall (October-November). A soil test can be submitted to your local County Extension Office and costs between $7-$12 depending on your particular extension. Be sure to note when submitting your soil test, that you want to get recommendations for hydrangeas. The County Extension will send your soil sample off for a test and you will get detailed instructions on what exactly needs to be added to your soil to feed your hydrangea plants and to keep them healthy.

While waiting for your soil test results to come back, you can do a quick test with 2 tablespoons (30 mil) soil + 1 tablespoon (15 ml) distilled water) and add vinegar. If your soil fizzes, your soil is alkaline! If there is no fizz, get a new sample. Test 2 tablespoons (30 mil) of soil + 1 tablespoon (15 mil) of distilled water + add baking soda. If your sample fizzes your soil is acidic. If it doesn’t fizz, soil is in the neutral 7.0 range most likely.

In the late fall or early winter months (when no snow is present), a top-dressing of compost will feed the soil micro-biology surrounding your plant and make nutrients available to your Hydrangea plant feeding it through the winter. You can also mix in some used coffee grounds and crushed egg shells into the soil and even a fine dusting of wood ash left over from your Green Egg (if you have one) or fire pit (just make sure any coals/ash scooped are cold). You can also add Bone Meal at this time which is slow to break down and only utilized by the plant with soil pH is below 7.0. These additions add acidity and alkalinity to the soil. But remember, these adjustments take three months or more to take effect, so act now if you haven’t prepped your soil beneath your beautiful hydrangea.

How to Get New Hydrangea Plant Starts with Little Effort

And while we are discussing fall / winter soil amendment strategies… if you take a low-lying branch from your Hydrangea and allow it to touch the soil and place a stick with a hook on the end (where you have broken off a branch from the main stem) or a metal u-pin if you have one on hand (even a light rock may do the trick) and essentially have the stem touch the soil and the “mother” plant will put down roots and create a baby plant come spring with adequate moisture. Check it again in 3-4 months and then prune that branch from the mother plant early spring (typically here in Georgia, you can see roots forming on propagated stems by late February.)

When to Prune your Hydrangea in Georgia

Hydrangeas (Bigleaf H. macrophylla, French, and Oakleaf H. quercifolia) flower buds from on old wood. Big Leaf cultivars include Mophead, Lacecap, Mountain hydrangeas. You want to prune these after flowering and shape your bush at that time.

If your Hydrangea is (Panicle H. paniculata, Smooth Hydrangea arborescens also called wild hydrangeas), flower buds will form on new wood, so prune when the hydrangea plant is dormant and remove spent blossoms after flowering (aka: deadhead). This will include your Snow Ball variety.

As a general rule, plants that flower before May ideally should be pruned following their bloom. Plant that flower after May can be pruned just prior to spring growth during dormancy (Jan/Feb). There are of course plants that are exceptions — those being late-flowering azaleas that bloom during May, June, or even July as well as the hydrangeas that bloom on old wood (mentioned above.)

You will want to prune away any disease, dead, stray or broken branches at anytime.

How to Change Your Hydrangea Bloom Color

Not all hydrangea species change color. White cultivars are an example of this, however, varieties such as Hydrangea macrophylla and H. serrata can range in color from pink to blue, fuchsia, plum and even periwinkle. High levels of aluminum in the sol plus having acidic soil pH will generate the coveted bright blue to purple flower shades.

For blue hues, you will want to use soil amendments like elemental sulfur and gypsum. You can also use an organic fertilizer containing cottonseed meal when feeding the plants. Adding aluminum sulfate to the soil isn’t necessary and could be harmful. Aluminum is plentiful and not an essential plant nutrient and too much of it can actually be toxic.

Recipe for blue flowering hydrangeas:
1/2 cup (120 ml) sulfur per 10 square feet (1 square meter) to alter the soil’s pH.

Recipe for pink flowering hydrangeas:
1 cup (235 ml) garden lime per 10 square feed (1 square meter) to alter the soil’s pH.

Remember, changing the pH of your soil is a gradual process that can take up to a year for the color change to take effect. You may also want to use pine straw as a mulch on top of the soil which will naturally break down over time, but will feed the micro-organism in your soil. Pine Straw, though minimal, may make your soil slightly more acidic over time and multiple applications. These hydrangea plants require plenty of moisture to get to the flowering stage, so put some sort of mulch (Pine Straw, wood chips, leaf mold, straw, or a living mulch that is a low spreading ground cover) down to help suppress weeds and maintain moisture. (Remember, you don’t want to ever have bare soil!)

How to Preserve Hydrangea Blooms to use in Home Decor

When your Hydrangea begins to bloom, pick a full new bloom in the morning and dry it slowly and hang upside down with a clothespin to a hanger in a room with good circulation (preferably indoors where humidity levels are lower due to Air Conditioning.) Allow the bloom to completely dry and then use in whatever decorating application. They are especially pretty as a wreath. Just spray with a clear craft finishing spray to preserve color. The also look pretty as a dried floral bouquet arrangement.

If you haven’t explored growing a hydrangea bush, I encourage you to give it a try! It’s a wonderful showy flowering bush that will bring enjoyment whether fresh or dried! Do you have a tip that has worked well in caring for your hydrangeas? Feel free to share in the comments below!

Happy Growing!

Erin

PS: If you are married, the Hydrangea is traditionally the fourth anniversary flower to give your love. I personally think any day and any year is a wonderful time to give a flower to someone you love. 😉

Erin Castillo is a wife and mother to five in Atlanta, Georgia. She grows food using organic methods for her family and also produces seed to sell, some of which is grown hydroponically and adapted to those growing conditions making it ideal for Tower Garden, FarmStand and Aerogarden home growers. If you want to check it out, you can find it at GYHG Seed Co. She is also certified in hydroponics and volunteers as a guest writer for her local gardening community.

Sources:

• Dorn Ph. D., Sheri and Sawyer, Sarah. Georgia Master Gardner Handbook, 8th Edition. University of Georgia Extension. Copyright 2021 University of Georgia College of Agricultural and Environmental Sciences ISBN 978-0-528-94356-8
• Monrovia “10 Things Hydrangea Lovers Should Know“
• Hudson, Jr., Charles. Hudson’s Southern Gardening Published by Topper and Love, Atlanta Georgia. Copyright 1953, 1958
• My mother (God rest her soul) who shared with me what worked for her gorgeous blooms and how she would dry them and save them for me to enjoy in my own home decor.
• For further reading: Success With Success With Hydrangeas: A Gardener’s Guides: A Gardener’s Guide Lovers