‘Summer Crush’ Hydrangea (Hydrangea macrophylla ‘Summer Crush’) is a popular reblooming bigleaf hydrangea, celebrated for its vibrant raspberry red or neon purple blooms. This compact shrub, reaching 18 to 36 inches tall and wide, displays continuous color from late spring through fall. Proper winter care is important for its survival and robust blooming.
Why Winter Care is Crucial
Winter care is important for ‘Summer Crush’ because, as a bigleaf hydrangea, it blooms on both old and new wood. This means it forms flower buds on both current and previous season’s stems. Protecting these old wood buds from harsh winter conditions, especially in colder climates, helps ensure a plentiful first flush of blooms in spring. While ‘Summer Crush’ is cold-hardy (USDA Zones 4-9), extreme cold or fluctuating temperatures can damage flower buds, impacting bloom production. Consistent winter protection safeguards these buds and promotes abundant reblooming.
Preparing Your Summer Crush for Winter
Preparing in-ground ‘Summer Crush’ hydrangeas for winter begins after a few hard frosts but before the ground freezes solid. Ensure adequate watering in late summer and fall, as well-hydrated plants handle winter stress better. The soil around the plant should remain moist, but not waterlogged, until the ground freezes.
Applying a thick layer of organic mulch around the base of the plant is beneficial. Use straw, shredded leaves, or wood chips to create a 4 to 6-inch deep layer extending a few inches beyond the root zone. This mulch insulates roots from freezing temperatures and helps retain soil moisture. For additional protection of above-ground stems and buds in colder regions or during severe cold snaps, consider wrapping the plant with burlap or creating a cage filled with dried leaves. This barrier shields delicate buds from wind and extreme cold. Pruning should be minimal; only remove dead or diseased branches, avoiding significant cuts that could remove potential flower buds.
Winterizing Potted Summer Crush Hydrangeas
‘Summer Crush’ hydrangeas in containers have distinct winter care needs, as their root systems are more exposed to cold. One option is to move the potted plant to a sheltered, unheated location, such as a garage, shed, or cool basement. In these environments, the plant enters dormancy, requiring minimal light and reduced watering (perhaps once a month if the soil feels dry).
For containers too heavy to move indoors, outdoor insulation is necessary. Grouping pots together offers collective protection. Wrapping containers with burlap, bubble wrap, or other insulating material helps protect the root ball from freezing. Applying a layer of mulch to the soil surface within the pot also provides insulation. During outdoor wintering, ensure the plant receives light watering if there’s no natural precipitation, preventing the soil from drying out completely.
Spring Transition and Beyond
As winter subsides and spring approaches, gradually remove protective coverings from your ‘Summer Crush’ hydrangea. Do this when the danger of hard frosts has passed, typically after the ground is no longer frozen. Removing protection too early can expose emerging buds to late-season cold snaps.
Once new growth appears, assess the plant for winter-damaged wood. Light pruning can remove dead or weak stems, cutting them back to healthy buds or where new growth emerges. Avoid extensive pruning, as this variety blooms on both old and new wood. As temperatures rise and new foliage expands, re-establish a regular watering schedule, ensuring the soil remains consistently moist. A slow-release granular fertilizer, particularly one with a higher phosphorus content, can be applied in early spring to support vigorous new growth and abundant blooming. Monitor the plant for signs of health and new bloom development.