Did your hydrangeas whisper “Feed Me” as you admired them today? If not, they should have because it’s high time for fertilizing hydrangeas. Although their needs are similar, you fertilize each variety a bit differently, so let’s take them a little at a time.
FERTILIZING BIG LEAF AND MOUNTAIN HYDRANGEAS
Your bigleaf (macrophylla) and mountain (serrata) hydrangeas should be flowering by now and if they are rebloomers, need encouragement to set up their second set of buds. If they are not rebloomers, they will soon set buds for next year, so get busy and give them a little love. What might that be?
Fertilizing hydrangeas with a basic tree/shrub product with an NPK ratio of 3-1-2, 6-2-4, etc. is the answer. You might be surprised to learn that rose fertilizer is ideal. Here’s just one you might see at a garden center.
Try to avoid using something like 10-10-10 or even 5-5-5. No plant uses nutrients in equal amounts and fertilizing hydrangeas in equal formulations just contributes to pollution. If you go the chemical route, use time release versions which are better for plants (they don’t jolt it).
How much fertilizer you use will depend on the size of your plant. There’s information on the package to guide you which you should follow. Don’t let it touch the trunk or stems of the plant. Make sure you carefully scratch in whatever you add. It’s best to gently water it in or apply it just before rain is forecast so it doesn’t get washed away.
THE BENEFITS OF COMPOST
If you don’t fertilize hydrangeas for some reason, minimally give the plants a little compost. Hydrangeas like well drained, humusy, fertile soil rich in organic matter. Over time this breaks down and needs to be replenished regularly. Although not technically “fertilizer,” compost improves drainage and adds important microbes on a gradual and steady basis while it improves soil health. It should always be part of your fertilizing regimen for these plants. A base of organic compost like Coast of Maine Lobster Compost is a great amendment which will feed the plant slowly and evenly.
Then add mulch to be sure the plant’s roots don’t dry out. Organic mulches like bark chips, shredded cedar, sweet peet, etc. are attractive and functional. Another mulch you can use is shredded leaves if you have some saved from last year. But if you have a pH sensitive plant with pink flowers that you want to keep that color, you might want to use some kind of stone mulch. Organic mulches may have too much acid in them which can change the color of your pH sensitive pink flowers so be mindful of that.
FERTILIZING OAK LEAF AND CLIMBING HYDRANGEAS
What about fertilizing your oak leaf (quercifolia) and climbing (petiolaris) hydrangeas? They need just about the same treatment. No need to worry about rebloom here as they don’t do that. You are feeding them simply to keep them healthy and happy. Keep in mind they like woodland environments so mimic that as best you can with your mulch.
FERTILIZING WOODLAND/SMOOTH AND PANICLE HYDRANGEAS
Your woodland/smooth (arborescens) hydrangeas like ‘Annabelle’ have been in full flower now for several weeks if not longer. Some of them like Incrediball® are rebloomers. All of them can use fertilizer. Stick with the shrub/rose fertilizer, compost, and mulch formula and you won’t be sorry.
Your panicle (paniculata) hydrangeas should be flowering just about now and they will appreciate some fertilizer to maintain their energy. You don’t need to worry about mulch impacting the color of these flowers as that’s not possible so mulch however you want to. Just be sure you do it. I’ve learned that the better the panicle hydrangeas are hydrated, the longer the flowers will last and the better the color will endure on them so don’t forget the mulching part of the process.
If your plants are languishing or you’re not satisfied with their performance, fertilizing with the right product at the right time is one easy thing you can do. Just start slowly and be deliberate about it. Then you can work on what else is going on to solve the problem.
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