How to Grow and Care for Strawberry Vanilla™ Hydrangea

Hydrangeas are known for the summer color that they bring to a landscape, and the strawberry vanilla hydrangea furnishes that color in style. 'Strawberry Vanilla' is the commercial trade name for a popular hydrangea cultivar, Hydrangea paniculata 'Renhy'.

This hydrangea changes its bloom color as the summer wears on. The blooms are pure white at first, but soon they begin to transition to a pale pink and mature to a deep maroon color. That color change does not happen uniformly across the flower head; the result is usually a bi-colored flower head. The pink color gradually becomes deeper, until, finally, you are left with a very attractive dark shade of maroon. But, for further variety, new stems with white flowers mix in with the pinkish-red of the older stems in late summer.

Strawberry Vanilla™ is usually planted as a potted nursery specimen in early fall or spring. Like most Hydrangea paniculata cultivars, it is a fast-growing plant that often achieves full size within a year.

Common Name	Strawberry Vanilla™ hydrangea
Common Name	Hydrangea paniculata 'Renhy' (brand name is Strawberry Vanilla)
Family	Hydrangeaceae
Plant Type	Deciduous shrub
Mature Size	6-7 ft. tall, 4-5 ft. wide
Sun Exposure	Full
Soil Type	Well-drained
Soil pH	Neutral to acidic
Bloom Time	Summer, fall
Flower Color	White, transitioning to pink, and then maroon
Hardiness Zones	3–8 (USDA)
Native Area	Cultivar, no native range; parent species is native to Asia

Strawberry Vanilla™ Hydrangea Care

Strawberry Vanilla™ hydrangea does best when planted in well-drained soil in a full sun location. Dig a large hole, about twice the diameter of the nursery container, and plant the shrub at the same height as it was in the container (top of plant crown at ground level). Backfill, then water thoroughly. This plant will quickly grow to five feet in diameter, so give plenty of space between shrubs.

This is a shrub that blooms on new growth, so prune it in late winter or early spring before new growth starts. It usually grows best as a multi-stem shrub, but you can also create a tree-like appearance by selecting a central leader and pruning off the other stems.

Light

Strawberry Vanilla™ hydrangea produces flowers most vigorously (and with the best color) in full sun, six to eight hours per day. With less than six hours of direct sunlight daily, plants will become overly leggy with fewer blossoms. Given a choice, they prefer to enjoy direct sun during the morning hours.

Soil

The primary soil requirement for strawberry vanilla hydrangea is good drainage—beyond that, any soil composition will suffice. This hydrangea prefers a neutral or slightly acidic pH, but isn't terribly fussy.

Water

This hydrangea has average water needs; the standard one inch of water per week rule will generally be sufficient. Lack of water might result in fewer flowers, so be sure to water during periods of drought in the summer and or spells of particularly hot weather.

Temperature and Humidity

Strawberry Vanilla™ hydrangea is reliably hardy in USDA cold hardiness zones 4 to 8 and can survive with winter protection in zone 3. It will tolerate temperatures down to minus 30 degrees Fahrenheit. In humid climates, it might be somewhat more susceptible to fungal diseases.

Fertilizer

If your soil is poor to begin with, feed regularly. The best thing to do in such instances is to amend the soil with plenty of compost every year. If you're not opposed to using chemical fertilizers, you can supplement the compost with the application of a slow-release, balanced fertilizer each spring once growth has begun.

Withhold all fertilizer after late July to allow the shrub to move toward winter dormancy.

Types of Hydrangeas

Strawberry Vanilla™ is a unique cultivar of Hydrangea paniculata, but note that there are many other kinds of hydrangeas. The Hydrangea genus has several distinct species that are cultivated as garden plants.

• Hydrangea paniculata: This species, which includes Strawberry Vanilla™, are often pruned into tree form and are sometimes known as tree hydrangeas, or peegees.
• Hydrangea macrophylla: The Latin name says it all, as this kind has big leaves and one of its common names is mophead hydrangea. This is the species where pH controls the color of the flowers. Acidic soil produces blue blooms, and alkaline soil produces pink blooms.
  
• Hydrangea quercifolia: Also known as the oakleaf hydrangea. This is a type valued more for its leaves (which resemble oak leaves) than for its flowers.
• Hydrangea arborescens: This plant is valued for its large flower heads, such as Incrediball® (Hydrangea arborescens 'Abetwo').
• Hydrangea petiolaris: This is a true vining and climbing hydrangea often trained on fences and trellises.

Pruning

Panicle hydrangeas such as Strawberry Vanilla™ flower on new wood that grows in the current season. It sets its bud in springtime for summer flowering. For this reason, it's important to do your pruning after it has flowered, in late fall, winter, or very early spring. Pruning at the wrong time (late spring or early summer) will reduce flowering if new growth. and therefore, buds is removed.

Hydrangeas should not be heavily pruned until they are quite mature, five or six years old. At this time, annual heavy pruning that removes up to one-third of the total growth can help keep the plant healthy and provide good air circulation to prevent fungal diseases. Regular heavy pruning also tends to create plants that produce larger, but fewer, flowers.

A badly overgrown shrub can even be chopped back to ground level; it will generally come back to full health within a single growing season.

Propagating Strawberry Vanilla™ Hydrangea

This is a trademarked, copyrighted cultivar that cannot be propagated by any means. Doing so can potentially invite legal consequences. Seed propagation is not an option, either, because the flowers of this cultivar are sterile.

Potting and Repotting Strawberry Vanilla™ Hydrangea

Container culture is not common for hydrangeas, but Strawberry Vanilla™ is a relatively small cultivar that can be grown in a large patio or deck container. Choose a pot at least 16 to 24 inches wide with drainage holes. It's best to use a frost-proof container, such as wood or plastic, as rigid clay or ceramic pots could split and shatter in below-freezing temperatures

Fill the pot with a standard commercial potting mix. Potted plants need more frequent watering and fertilizing, but stop fertilizing in late July to allow the plant to move toward winter dormancy. Hydrangeas will need to be repotted every few years as they become root bound. Once you reach a maximum pot size, it's possible to root-prune the plants every few years, replanting them in the same container filled with new soil.

Container-grown plants should be over-wintered by moving them to a sheltered location.

Overwintering

Panicle hydrangeas are normally very winter hardy to USDA cold hardiness zone 4, and they will usually survive nicely without any winter protection. But in zone 3, it's a good idea to water the shrubs well going into winter to prevent desiccation from cold winter winds. Covering the root zone with a few-inches-thick blanket of mulch or compost for the winter is also a good idea in extreme climates.

In all regions, stop feeding from mid-summer onward after the flowers have appeared because you want to avoid stimulating new growth that can be injured by cold winter winds.

Common Pests & Plant Diseases

This hydrangea can suffer from a few different diseasess (such as bacterial wilt, blight, leaf spot, mildew, and rust), all of which can be minimized by providing plenty of space (to promote air circulation) between your Strawberry Vanilla™ hydrangea and any other plants.

Insects such as aphids and mites can also attack it; be on the lookout for them and, upon detection, spray immediately with neem oil organic insecticide.

How to Get Strawberry Vanilla™ Hydrangea to Bloom

This shrub normally begins blooming in midsummer, with large flower panicles that begin white, then gradually transition through pink to pinkish maroon by fall. The dark color will maintain for three to four weeks before turning paper-brown—though the browned flower heads are also attractive and serve as winter interest. Larger blooms can be created if you prune off all but six to ten of the main stems.

Failure to bloom is often traced to a lack of water, poor soil, or a lack of adequate sunlight. Regular water and fertilizer are essential for good blooming. There are other possible reasons why these plants don't bloom:

• Plants that are getting too much nitrogen fertilizer sometimes don't flower because they put most of their energy into producing foliage. This can happen when a shrub is surrounded by turf grass that is regularly fertilized.
• Improper pruning—removing new growth in the late spring or summer—will also reduce flowering. These plants set their buds and flower on new growth so should be pruned during their dormant period in winter or very early spring.

Common Problems With Strawberry Vanilla™ Hydrangea

Panicle hydrangeas are generally quite trouble-free, but some growers are annoyed by the way the heavy flowers cause the stems to droop. This can be remedied by making sure the plant has plenty of sunlight and keeping it closely pruned to prevent it from getting too tall.