Pro Growing Guide for Hydrangeas

The beautiful hydrangea is a gardener's favorite all over the world. For centuries, the elegant appearance and classic colors of hydrangea shrubs have made them a favorite in homes from the urban center to the rural countryside.

Although relatively easy to grow, the plants need some care and attention. The level of necessary work will depend on the varieties you choose to plant.

An Asian native species, this shrub is well-adapted to the United States and can thrive in USDA plant hardiness zones three through nine. Selection boils down to the gardeners finding which hydrangea shrubs work in their specific areas. This plant prefers a sunny spot in the yard and demands at least six hours daily to bask in the sunshine. However, it can also tolerate some shade, particularly in the afternoon.

It loves woody, moist soil--but don't over wet it, as too much moisture can cause rot, mold, and mildew. This post will take a deeper dive into hydrangeas and provide you with all the growing information you’ll need to set yourself up for a pleasurable experience and beautiful, blooming hydrangea shrubs.

Hydrangea Varieties

There are two main categories of hydrangeas; those that flower on old growth and those that flower on new growth.

NOTE: Old-growth hydrangeas are not popular with most gardeners due to their "picky" nature, but it is at least worth noting their existence to avoid purchasing them by mistake. We carry the better-natured new-growth variety at TN Nursery.

Old-Growth Hydrangeas

These hydrangea varieties grow from the ground up. They will start flowering when they reach a certain height—usually around one to two years after planting.

Although they are lovely, they also require a bit more patience. Most gardeners prefer the second type, new-growth hydrangeas.

New-Growth Hydrangeas

These varieties bloom on the previous year's growth and will kick off the flowering process when new shoots grow from their root system.

Some of the most popular new-growth hydrangeas you can plant in your garden include Pee gee Hydrangea (Hydrangea paniculata Grandiflora), the lovely Nikko Blue Hydrangeas Snow Hill Hydrangea, and Smooth Hydrangeas (Hydrangea arborescens)..

Hydrangea Colors

Gardeners select many different species of Hydrangeas for their flower colors. You will find an array of blues, purples, reds, pinks, and whites.

Hydrangeas famously "change colors," depending on soil quality. Thus, you might get a different color than you expected.

What causes hydrangea colors to change?

That phenomenon is a result of your soil's acidity level. The earth contains many natural minerals and metals, including aluminum--which needs acidity for absorption and determines the hydrangea flower color.

Selecting Hydrangea Plants

When choosing the specific hydrangea varieties you want to plant in your garden, consider their color patterning and how tall they will grow.

For example, white flowers usually work best when planted against dark-colored fences or leafy, dark-green trees. That is why gardeners often select Snow Hill Hydrangeas as a backdrop for richer-colored flowers like roses and daylilies.

It would help if you also consider your climate and the length of time you plan to grow your hydrangeas. Some varieties will only flower in certain temperatures at certain times of year—and they may not even bloom when planted outside their ideal conditions.

When and How to Plant Hydrangea Flowers

The best time to plant hydrangea is in the spring after all the danger of frost. However, if you do not get fall frost in your local climate, you can install them in late summer or early fall.

●Dig a hole that is twice as wide—and just slightly shallower than the container they are currently in—then fill the bottom of the planting hole with a mix of composted organic matter and soil from around your garden, so there will be a mixture of nutrients for the roots to soak up.

●Place your hydrangea plant(s) in the ground and backfill it with more organic material, making sure that there is a slightly raised mound around the stem of each plant, as they will usually produce new roots from where those stems meet the soil surface.

●You also want to ensure that the plants are growing straight, not leaning to one side or another, as this can cause problems later on when they try to grow too large for their allocated space.

●Water thoroughly after planting and continue to do so every few days until the soil becomes moist.

●If you live in a climate with snow, remove any that accumulates over your hydrangea buds during winter. This will help protect them from cold damage and help them blossom the following year.

●Add an inch to two inches of hardwood mulch around the base of your hydrangea after the growing season. The wood will break down and release nutrients. Plus, it will insulate your plant against frigid winter temperatures.

Hydrangea Flowers Care Needs (They have such an easy-going nature!)

Hydrangea's quick growth rate and low-maintenance needs have earned it the reputation as the perfect flower you can plant once and then sit back and enjoy.

Here is some information regarding caring for established shrubs.


●Hydrangeas typically grow best in finely mulched, well-drained soil with a slightly acidic pH.

●If your plants appear to be wilting or not thriving even though they are receiving adequate water, the first thing you should check is the soil's pH level.

●Add lime to raise your soil's pH level if it is acidic, and add sulfur if it is alkaline.

●A good practice is monitoring the soil's pH and adjusting it as needed to ensure that it doesn't fall below a range of five or over nine, which will also damage the plants.


●Most variants of hydrangea grow best in full sun exposure, requiring a minimum of six to eight hours of sunlight per day. However, some will tolerate partial shade--with less prolific blooming.

●Space the plants adequately for enhanced air circulation and an effective leaf-drying process after rain showers.


●Hydrangea flowers need one to two inches of water every week to thrive and grow into large, healthy bushes.

●If they receive too little water, the blooms will dry up and drop from the stems; if they receive too much water, they will become limp and unattractive.

●Use either a soaker hose or drip irrigation system to water the plant's roots directly, where it's most effective.


●Hydrangeas flourish when given a slow-release fertilizer every six weeks from spring through fall.

●A high-nitrogen fertilizer will boost blooming by stimulating new growth in the plants.

●However, feed them appropriately, as you may otherwise have leafy and thick plants with very few blooms.

●Do not fertilize after the blooming period is over unless you want to encourage new growth for next year—then only use organic fertilizer, as it will be much less harmful than chemicals would be.

Temperature and Humidity

●Hydrangea plants prefer pretty mild temperature zones–check your USDA growing zone for a species that will perform well for you year after year.

●Too much exposure to cold weather can cause the blooms to drop off the stems. If this happens, don't worry - your plants will still grow new flowers in spring.

●If you reside in a USDA zone with frigid wintertime temperatures, protect your hydrangeas by removing all foliage on their stems and branches and covering them with a one- to two-inch thick layer of mulch.


●Prune your hydrangeas in fall or early spring to remove dead blooms and stems, crossing stems and branches that grow at odd angles.

●In addition, you should stake tall blooming stalks during the growing season. This practice will reinforce them so they can hold up the flowers.

Pest control for Hydrangea Plants

Hydrangea plants are hardy and generally pest-resistant. But what do you do if you experience an issue anyway? Here are a few things to keep in mind:

●Several pests may impact your hydrangea plants, including aphids, Japanese beetles, and spider mites.

●Ladybugs are your friend--they eat aphids and spider mites. If you see them, let them be!

●Using an alcohol-soaked cotton ball or swab, you may manually wipe aphids from the leaves. For other pests, apply insecticidal soap or horticultural oil according to manufacturer instructions.

●Be sure to spray your entire plant, including the undersides of the leaves.

The Takeaway: Hydrangea Shrubs Are a Lovely, Good-Natured Addition to Your Landscape

Hydrangea shrubs require minimal care and come in an extensive range of colors to suit almost any color story. Once you master the care techniques, you will have a lovely, long-lived plant for decades to come.

TN Nursery has healthy and robust hydrangea shrubs that will add vibrant floral colors and beautiful foliage to your garden from spring until the late summer every year. Please explore our website and feel free to purchase with complete confidence in our plant health and friendly customer service. Hydrangea How to care and grow.