We get a lot of questions on how to maximize blooms on Endless Summer® Hydrangeas. In reality, they’re pretty easy-care and sometimes get overthought. One of the best things you can do is – after doing your quick spring clean up – to fertilize your shrub with a slow-release fertilizer. Now, you don’t want to overdo it, because over-fertilizing can actually slow down your bloom growth. Seems counterintuitive, but it’s true. You don’t want to live in excess!
So, once you’ve pruned any stems that didn’t survive the winter and you start to see green leafy growth, follow package instructions on how much fertilizer to apply. As mentioned, we recommend a slow-release fertilizer that is high in phosphorus. That is the element that encourages bloom production. If you’re not sure which one to try, as your local garden center expert for a bloom-boosting, slow-release fertilizer with a high percentage of phosphorus. They should be able to help with the exact kind in their store.
Once you’ve done the application in spring, you can just leave your hydrangea the rest of the season. If you’re anxious to apply more and the package instructions say it’s ok, follow their directions and apply again mid-summer. You definitely don’t want to apply fertilizer once you get too close to fall or it’ll cause it to keep pushing out flowers instead of letting it shut down for fall. One other thing to note is that we get a lot of homeowners that apply the Color Kits, hoping that will fertilizer their plants. Unfortunately, that’s not what happens. The Color Kits are designed to simply adjust the pH of the soil to change the color of the blooms. There is no fertilizer in this, so you want to be applying both in spring (if you want to change your bloom color)!