Panicled hydrangea ‘Renhy’ boasts conical flower clusters that fade from white to rosy-pink as the season progresses. This deciduous shrub flourishes in well-drained soil, reaching up to 8 feet in height. Its pointed, dark green leaves enhance the showy blooms, which together attract pollinators and add dramatic flair to any garden setting.
I. Appearance and Characteristics
Vanilla Strawberry hydrangea (Hydrangea paniculata ‘Renhy’) was introduced in 2009. Around midsummer, buds open into densely clustered white flowers with pinkish centers. The flower heads take on a deeper and richer blush as they age. The huge, cone-shape blooms form continuously all summer long, giving this shrub a multi-colored effect with bright-white new blooms complementing reddish-pink ones. The unique rosy coloring lasts several weeks and features showy red stems.
Hardy in Zones 3-9, this shrub is easy to care for and will grow in most areas of the country.
II. How to Grow and Care
Sunlight
Vanilla Strawberry 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.
Temperature and Humidity
Vanilla Strawberry 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.
Watering
The primary soil requirement for this hydrangea is good drainage—beyond that, any soil composition will suffice. This hydrangea prefers a neutral or slightly acidic soil pH, but isn’t terribly fussy.
Soil
The primary soil requirement for this hydrangea is good drainage—beyond that, any soil composition will suffice. This hydrangea prefers a neutral or slightly acidic soil pH, but isn’t terribly fussy.
Fertilizing
If soil is poor, provide nutrients to this shrub regularly. The best method 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 an 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.
Planting Instructions
The best time to plant Vanilla Strawberry is in spring before rapid growth sets in and in late autumn, just as this panicle hydrangea is dormant. Dig a hole that’s deep enough and wide enough for the root ball to sit comfortably in. Ensure the stem is at the same soil depth as it was in its container. Mulch around the base to retain soil moisture and suppress weeds.
Space the hydrangeas 4 feet apart for a dense, continuous hedge. Specimen plants that you want to stand out should be planted at least 5 feet apart.
Depending on the size you’re starting with, expect your plant to bloom a year or two after planting.
Pruning
This type of hydrangea blooms on new growth instead of the previous season’s stems, as some other hydrangea varieties do. That means you don’t need to worry about cutting off the next season’s blooms when you trim your plant or when a late spring frost zaps all the flowers for the season. Plus, the blooms that remain at season’s end provide wintertime interest; they’ll dry and turn a parchment color.
To remove the old flowers to make way for new ones, and to encourage new growth, the best time to prune this hydrangea is after the worst of winter’s cold has passed—most likely in February or March. You can trim it back by as much as a third every year.
Propagation
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 because the flowers of this cultivar are sterile.
Potting and Repotting
Container culture is not common for hydrangeas, but Vanilla Strawberry 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.
How to Get to Bloom
This shrub normally begins blooming in midsummer with large flower panicles that begin white, then gradually transition through pink to strawberry red by fall. The dark color will last 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. Other possible reasons why these plants don’t bloom are:
- Plants that receive 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 stem growth in the late spring or summer—will also reduce flowering. These plants set their buds and flower on new stem growth so should be pruned during their dormant period in winter or very early spring.
Pests and Diseases
Common Pests & Plant Diseases
This hydrangea can suffer from a few different diseases (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 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.
Common Problems
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.
III. Uses and Benefits
With proper care, your Panicle Hydrangea will reward you with its beautiful cone-shaped blooms, which can change color from white to pink as they mature, adding elegance and charm to your garden or landscape.
