How to Fertilize Endless Summer Hydrangeas to Boost Their Flower Power

Keep the show going all season long by giving these reblooming shrubs the exact nutrients they need.

Popular bigleaf hydrangeas got a major upgrade in 2004 with the development of Endless Summer, the first reblooming hydrangea variety. Instead of just producing a limited number of flowers on “old wood” that the plant grew the previous year, Endless Summer produces new stems and new flowers continually. And now, the Endless Summer collection includes five unique varieties (the newest is ‘Summer Crush,’ a compact, container-friendly shrub with flowers that can vary from raspberry red to vibrant purple). But all that constant growth and flowering use up a lot of nutrients, so it’s important to give your reblooming hydrangeas the fuel they need in the form of an easy-to-use fertilizer, applied at the right times in the season.

Best Fertilizer for Endless Summer Hydrangea

Feeding your reblooming hydrangea begins with the right product. Your local garden center’s fertilizer section likely has an overwhelming number of options to choose from, so it’s important to know exactly which kind to seek out. “You’re looking for a slow-release granular fertilizer that is labeled ‘bloom boost,’” says Endless Summer expert Ryan McEnaney from Bailey Nurseries. Bloom boost fertilizers such as Flower-tone ($10, Ace Hardware) have a higher level of phosphorus, the nutrient that promotes flower formation. Phosphorus is the middle number in the N-P-K nutrient label.

Related: 6 Interesting Facts You Didn’t Know About Hydrangeas

A slow-release fertilizer is packaged into tiny pellets that slowly break down, supplying nutrients over weeks or months. This product just needs to be sprinkled onto the soil around the base of your plants, then watered lightly. As always, follow package directions when applying fertilizer to make sure you use the correct amount.