Hydrangea help

Hi Everyone,

New gardener here and looking for advice on one of my container hydrangeas. It's looking really spindly and branches are all over the place. I have no idea how to prune it and very confused by the old wood/new wood. Can anyone help?

Thanks in advance!

 

Hello, HazzaGrazza. Hydrangeas (and I am now referring just to the macrophyllas, also called mopheads or lacecaps) have an area in their base where they develop all the stems from. It is called the crown over here. New, green shoots in Spring that come out of the crown and that develop into stems are referred to as 'new wood'. The stems from last year are simply called 'old wood' and they are usually mostly sandy/light brown (in Spring) and green near the top/ends.

The flower buds: Hydrangea stems develop invisible flower buds at the ends of the stems. Those buds are inside the stem for protection during winter. Hydrangea macrophylla develops these flower buds always in July over here... later if one is further north. These flower buds open in the Spring and resemble small broccoli heads.

Your old wood stems should soon start opening these flower buds. I have a lacecap that started showing broccoli heads a week ago or so.

Why am I talking about those flower buds: well, pruning the ends of an old stem now could result in cutting off this year's bloom(s) from that specific stem. If you were to prune every single stem then you may not get any blooms this year. I say "may" and "could" because the stems have some back-up flower buds called adventitious flower buds that could produce blooms. They are located below the "main" flower buds and serve as "back-up". But if you make the stem cut waaaay down the stem, you may also cut off these back-up flower buds! So, many people try to be careful when pruning macrophyllas in Spring. Or they don't prune them. The best time to prune the stems is after they have bloomed (so you enjoy the blooms) but before the stems develop more flower buds again.

So, which stems should you prune: Well, you could prune (all the way down) the old stems that are too long and spindly now. Or you could prune only the long stems and only just a bit. Or you cut off the stems that are not growing straight up. Or you could prune stems that cross. Or you cut prune all the stems such that they all have the same exact length. Or you could even let all the stems bloom for a while and then prune by the end of June. Your choice. Whatever looks good to YOU.

To complicate things just a tad: New, green stems that develop from the ground in Spring may or may not also produce flowers this year too... it depends on what variety of macrophylla you have. There are many, newly introduced, varieties of mopheads and lacecap hydrangeas (the Endless Summer Series, Together & Ever Series, Let's Dance Series, etc.) that can produce flowers from old stems (as described above) and from new stems. These varieties bloom on old and new wood. They are called rebloomers in ads but, they are actually remontant. With remontant mopheads, for example, the same stem is not producing blooms multiple times. Rather old stems first produce flowers in early Spring and then the new stems produce flowers later in the growing season. The way that second flush of blooms works is, as the new stems get taller and older enough, they develop flower buds and these quickly open. So you get flower bud production from them in late Spring to mid Summer, followed by the quickly opening of those flower buds.

Bottom line regarding pruning... I would first let the shrub produce blooms from all stems now (just for personal enjoyment reasons only). Then, after you get tired of the blooms (hopefully before the end of June), decide which ones of those long stems to cut and how much to cut.

Which ones to cut: this should be decided by thinking of things like: aesthetics (what YOU think looks best; for example: prune to reduce plant size; deadhead spent blooms; prune to only keep stems that have about the same length and are growing upwards, i.e., not flopping down), security (not applicable in this case but, think in terms of removing stems that could make people slip and-or fall; sunlight (allow sunlight to enter into shady parts of large hydrangeas, specially tree or standard hydrangeas); prune branches that cross (this can promote flopping of branches), etc. An easy choice: you can cut the long, flopping ones; cut them all the way down or only a bit. Whatever you prefer.

If you decide to prune later on so you get to enjoy all the blooms from all the stems, mark the ones you decide to cut now. Use a green string so you can "find" those stems again... when the foliage has grown sooo much that you cannot easily tell which stems you originally wanted to cut. ;o)

Hints in case you decide to prune now: any small cuttings that you make can be used to produce a brand new, free, potted hydrangea. If a stem is too long for a small cutting, make another cut to prune off a small cutting from the end. Hydrangea mophead/lacecap cuttings are very easy to propagate as long as you put them in a potting mix for acidic plants, keep them in bright shade and maintain the soil as evenly moist (not wet or soggy) as you can. I realize you said you are a new gardener but the cuttings usually are easy to grow (a large percentage successfully "takes"). Here are some steps if you are interested in doing this: Taking Hydrangea Cuttings - Seasonal Gardening

Does that help you? Luis