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Planting, Growing, and Pruning Hydrangeas
Planting
Most hydrangeas prefer partial sun with full sun in the morning, followed by some afternoon shade. This is especially true for the Bigleaf hydrangea (H. macrophylla). Some varieties are more tolerant of full sun. Most hydrangeas will thrive in fertile, well-draining soils that receive plenty of moisture. The suggests, 鈥淚f your soil is draining too quickly, add garden mulch.鈥 Add compost or aged manure to enrich poor soil.
When to Plant Hydrangeas
Autumn is the best time to plant hydrangeas, followed by spring. Plan to plant the fall before the first frost or in the spring after the last frost. The idea is to give this shrub plenty of time to establish a healthy root system before the heat of summer or the extreme chill of winter, which makes the cooler shoulder seasons the best times to plant.
Plant the shrubs in the early morning or late afternoon. It鈥檚 generally cooler, and the plant is less likely to wilt because of extreme heat.
How to Plant Hydrangeas
- Space hydrangeas anywhere from 3 to 10 feet apart, depending on the type. Always space plants based on their expected size at maturity!
- Gently remove the hydrangea from its container and inspect the root ball, snipping off any dead or rotting parts. suggests, 鈥淏efore planting, check the root quality of container-grown plants and loosen the roots if they appear pot bound or to be circling the container.鈥
- Dig a hole as deep as the root ball and 2 to 3 times as wide. The base of the plant (where the stem meets the soil) should be level with the top of the planting hole.
- Set the plant in the hole and half-fill it with soil. Water generously. After the water is absorbed, fill the rest of the hole with soil and water again.
How to Grow Hydrangeas from Cuttings
Hydrangeas can easily be grown from cuttings. They root readily, and the process makes for a great lesson in propagation. Here鈥檚 how to do it:
- Find a new branch on a well-established hydrangea鈥攁 branch that has not flowered and bears three or more pairs of leaves. (New growth will appear lighter in color than old, and the branch will not be as rigid.)
- Cut 5 to 6 inches from the tip of the branch. Discard the bottom piece.
- If the tip cutting has at least two pairs of leaves, remove the lowest pair of leaves flush to the stem or at the node. If the remaining leaves are large, cut them in half, removing the tip half. Dust the cutting鈥檚 end with rooting hormone and, if desired, an antifungal plant powder. This will encourage rooting and discourage rotting.
- Fill a small pot with moistened potting mix. Plant the cutting, sinking it up to the first pair of remaining leaves. Water lightly to eliminate any air gaps around the stem. Cover the pot and the cutting loosely with a plastic bag (to maintain humidity). If necessary, use chopsticks or kebab skewers to prop up the bag so that it does not touch the leaves; if it touches the leaves, they might rot. Place in a warm area, sheltered from direct sunlight and wind. Water when the top layer of soil is dry.
- After a week or so, gently pull on the cutting. If you feel resistance, roots have formed. If there is no resistance, check for rotting.
Layering Hydrangeas
For bigleaf hydrangeas, in summer, dig a trench next to the plant, near a branch that easily reaches beyond the trench. Where the branch contacts the soil, remove an inch of the outer bark all around it. Bury the bared portion, pinning it with a florist鈥檚 pin or a gentle weight, leaving 6 to 12 inches of the end of the branch tip uncovered. Water regularly. In early spring, the branch should be ready to be removed from the mother plant and transplanted!
Growing
Watering Hydrangeas
- For the first 2 years after planting and during any drought, be sure your hydrangeas get plenty of water. If possible, water in the morning to prepare hydrangeas for the heat of the day and to avoid disease.
- Water at a rate of 1 inch per week throughout the growing season. Deep soaks 3 times a week (with a soaker hose or the like that keeps moisture off flowers and leaves) encourage root growth more than frequent sprinkles.
- All varieties benefit from consistent moisture, but bigleaf and smooth hydrangeas require more water. If the soil is too dry, leaves will wilt and flowering will be hampered.
- Add organic mulch underneath your hydrangeas; this will help keep the soil moist and cool, add nutrients over time, and improve soil texture.
Fertilizing Hydrangeas
Hydrangeas in rich soil seldom need fertilizer: Too much encourages leafy growth over blooms. The best way to determine your fertility needs is by using a soil test.
Apply fertilizer based on your specific hydrangeas. Each variety has different needs and will benefit from different application timing.
- Bigleaf hydrangeas can benefit from several light fertilizer applications in March, May, and June.
- Oakleaf and panicle hydrangeas do best with two applications in April and June.
- Smooth hydrangea plants only need fertilization once, in late winter.
Winter Protection
- In the fall, cover plants to a depth of at least 18 inches with bark mulch, leaves (not maple), pine needles, or straw. If at all possible, cover the entire plant, tip included, by making cages out of snow fencing or chicken wire and loosely filling the cages with leaves. (Do not use maple leaves, as they tend to mat when wet and can suffocate the plant.)
Pruning Hydrangeas
Many of our readers鈥 questions involve pruning hydrangeas. And no wonder鈥攊t鈥檚 confusing and depends on the variety of hydrangea. Luckily, as long as you know which type you鈥檝e got, it鈥檚 easy to figure out what sort of pruning technique to employ. (The more common garden hydrangea shrub is the bigleaf variety) Learn the essentials below.
| Hydrangea Type | When to Prune | Where Flowers Appear |
|---|---|---|
| Bigleaf (H. macrophylla) | Summer, after flowering | On old growth |
| Oakleaf (H. quercifolia) | Summer, after flowering | On old growth |
| Panicle (H. paniculata) | Late winter, before spring growth | On new growth |
| Smooth (H. arborescens) | Late winter, before spring growth | On new growth |
| Mountain (H. serrata) | Summer, after flowering | On old growth |
| Climbing (H. anomala ssp. petiolaris) | Summer, after flowering | On old growth |
Bigleaf (H. macrophylla), oakleaf (H. quercifolia), mountain (H. serrata), and climbing hydrangeas (H. anomala spp. petiolaris) are pruned AFTER the flowers fade in the summer. These varieties bloom on the previous season鈥檚 stems (鈥渙ld wood鈥).
- Flower buds actually form in the late summer and flower afterward in the following season, so avoid pruning after August 1.
- Only cut away dead wood in the fall or very early spring.
- To prune, cut one or two of the oldest stems down to the base to encourage branching and fullness.
- If the plant is old, neglected, or damaged, prune all of the stems down to the base. You鈥檒l lose the flowers for the upcoming season but also rejuvenate the plant for future years.
- It鈥檚 best not to deadhead (remove faded blooms) on the big mopheads; leave them over the winter and cut them back in early spring (to the first healthy pair of buds). It鈥檚 fine to deadhead the lacecaps; cut down to the second pair of leaves below the flower head.
- When growing H. macrophylla (and H. serrata) varieties in Zones 4 and 5, do not prune unless absolutely necessary, and then do so immediately after blooming. Otherwise, remove only the dead stems in the spring.
Panicle (H. paniculata) and smooth (H. arborescens) hydrangeas are pruned BEFORE flower buds are formed. These varieties bloom on the current season鈥檚 stems (鈥渘ew wood鈥).
- Prune in the late winter when the plant is dormant. This means that if the buds are killed during the winter, the plant will produce new buds in the spring, which will produce blooms.
- In general, prune only dead branches and do not prune to 鈥渟hape鈥 the bush.
Read more about how to prune hydrangea types.
How to Change the Color of Hydrangea Flowers
The colors of hydrangea flowers can be changed, but not instantly. Color correction takes weeks or more, and not every cultivar is changeable: White flowers are not affected by soil pH, the condition that imparts the blue and pink hues. Some bigleaf hydrangeas鈥攅specially mophead and lacecap types鈥攁nd mountain hydrangea cultivars change color based on the soil pH.
Acidic soils with a pH of less than 5.5 produce blue flowers; soils with a pH greater than 6.0 produce pink flowers. Do a soil test to determine the existing pH and amend as indicated to change it.
A plant should be at least 2 years old before undergoing a pH change; this will give it time to recover from the shock of its original planting. Also, note that it鈥檚 easier to change blue flowers to pink than pink to blue.
See How to Change the Color of Hydrangea Flowers for more information.
Types
For a more detailed overview of the many types of hydrangeas, check out Hydrangea Varieties for Every Garden.
There are two main groups of hydrangeas:
Group 1: Plants that Bloom on New Growth (This Year鈥檚 Stems)
The following hydrangeas, which form their buds in early summer on new growth, will flower reliably each year, requiring no special care.
- Panicle hydrangeas (Hydrangea paniculata)
- 鈥楪randiflora鈥 and 鈥楶eeGee鈥 are large old-fashioned, floppy varieties; 鈥楾ardiva鈥, 鈥榃hite Moth鈥, and 鈥楶ee Wee鈥 fit the scale of small gardens. 鈥楲imelight鈥 produces cool-green flowers and grows to a height of 6 to 8 feet.
- Smooth hydrangeas (H. arborescens)
- 鈥嬧嬧嬧婰ook for the cultivars H. arborescens 鈥楪randiflora鈥 and 鈥楢nnabelle鈥, which produce many large (up to 14 inches across), tight, symmetrical blooms in late summer.
Group 2: Plants that Bloom on Old Growth (Last Year鈥檚 Stems)
If you live in Zone 8 or warmer, choose plants from this group. Gardeners in cool climate zones will find many of them a challenge, because they set flower buds in the fall. Although hardy to Zones 4 and 5, the buds are prone to damage by an early frost in fall, a late frost in spring, or excessively cold temperatures when dormant in winter. This, along with untimely pruning, can result in inconsistent or no flowering.
- Oakleaf hydrangeas (H. quercifolia)
- You can expect an exceptional fall color from 鈥楽now Queen鈥, 鈥楽now Flake鈥, and 鈥楢lice鈥.
- Bigleaf hydrangeas (H. macrophylla)
- We love 鈥楢ll Summer Beauty鈥 (mophead), which has profuse, dark blue flowers that turn pinker in soils with near-neutral pH. If buds are winter-killed, the plant will form new ones in spring and still bloom.
- 鈥楴ikko Blue鈥 (mophead) is vigorous, with large, rounded, blue flowers.
- 鈥楤lue Wave鈥 (lacecap) produces rich blue to mauve or lilac-blue to pink flowers.
- 鈥楥olor Fantasy鈥 (mophead) has reddish or deep purple flowers and shiny, dark green leaves. It grows to about 3 feet tall.
- Mountain hydrangeas (H. serrata)
- 鈥楤luebird鈥 and 鈥楧iadem鈥 are early bloomers. In acidic soil, 鈥楶reziosa鈥 produces blossoms of an extraordinary blend of pale shades of blue, mauve, violet, and green.
- Climbing hydrangeas (H. anomala ssp. Petiolaris)
- 鈥楩irefly鈥 boasts variegated foliage.
Harvesting
Cut fully mature hydrangea flowers in the morning after you have watered the plant.
Immediately place fresh stems in cold water to prevent wilting.
- Recut the woody stems at a slant underwater.
- Remove the lower leaves on the stems.
- Arrange them in a vase and place them in a cool location, out of direct sunlight.
- Check the water level and quality daily. Change the water if it becomes cloudy.
- Mist the blooms with water. Soak wilting blooms in cool water for 10 to 15 minutes to revive them.
Use dried hydrangea flowers to create a wreath or other decorations around the house:
- Cut the flower heads when the flowers have matured and developed a papery consistency.
- Remove leaves from stems, and hang them upside down in a warm, dry, dark, airy room.
- When completely dry (usually a couple of weeks), store in a dry location out of direct sunlight.
- To enhance flower color, spritz dry flowers with diluted fabric dye.
Here are four alternative ways to dry and preserve your flowers.
Catherine Boeckmann
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Good Morning. I have 2 plants that are about 5-6 years old,that were the same size and planted at the same time. They are approx. 3 feet apart. For the last 3-4 year one of them grows very well while the other does not grow much at all. Right now one is about 20"tall and 17" wide, full of blooms and healthy. The other is about 8" tall and 6" wide with a couple of small blooms. Any ideas as to why there is so much difference between the two plants? Thank You
I also have four hydrageans plants next to one another. I've had them for four years. We live in the Phila. area. Only one of them blooms, but only two flowers. I've heard that this plant blooms better when plant by itself. Any truth on this and what am I doing wrong? All were bought at garden centers.
We have two of these in the front of our house next to one another. Both are two tears old. One blooms with quite a few flowers and the other is taller ( leafier) with healthy looking leaves and had one weak bloom which died off quickly, and nothing else. Same soil. Thanks
My hydrangea (oak leaf, just planted this spring) accidentally got run over by the lawn mower, sliced it right to the ground. I'm sick about it. If I were to leave it (the roots) in the ground, is there any chance it will live to be a viable shrub? Should I dig it up a start over with a new plant?
Hi Nick,
Hydrangea are hearty plants that will grow back when cut (even to the ground) during dormancy. However, a young, recently planted hydrangea like yours will not have as strong of a root system developed yet as a several year old plant would. Try waiting a while to see what happens during this summer: The plant might bounce back and start growing new shoots! If by next spring it’s still not doing well, plant another in its place. Good luck!
I planted 5 hydrangea (mophead) last summer and they have not gotten any bigger than they were when I planted them. They died back over the winter and then came back, but have not continued to grow (they did bloom). They are in a shady spot of the yard and they have bloomed. Too much shade? Can they be transplanted?
Hi Karen,
Hydrangeas like some, but not full shade; it sounds like they could not be getting enough sun. You can transplant them, but wait until the fall to do it. Once all of the blooms have died and almost all of the leaves have dropped, transplant the hydrangeas into a slightly sunnier location with well-draining soil. Layer some compost around the base to give them an extra boost in the spring.
I have a Harlequin macrophylla hydrangea that last year and this year had a few solid white blooms on one branch instead of the bicolor bloom that is normally seen. Is this a frequent occurrence? If the branch is rooted is it likely to continue to produce white blooms?
When hydrangea flowers begin with a color and fade to white, it’s usually an older bloom and past its prime for pollination. However, you’re saying the flower was white from the very beginning? Our guess is that your plant was hybridized using a white blooming hydrangea with a pink/blue blooming hydrangea, and some of the plant is showing its original white. In this case, yes, it will stay white. White flowers can not be changed.
My hydrangea never seem to bloom. We have healthy green leaves, but no flowers. We have one plant in the front of the house and one in the back. One gets full sun in the morning, one in the afternoon. Same problem with both plants :-(
