Azalea Pruning
For our TWIG topic this week, a more 'nuts and bolts' bulletin, I want to talk about azalea pruning and shearing. Across the mid-Atlantic, azaleas are cycling through to the end of their blooming season. We have had weeks of bloom, with early and mid-season varieties wrapping up their show, while some of the later season varieties are still at it and even still to come. At some point we can go through the azalea varieties - ' A Growing Conversation'? Meanwhile, it's time to sharpen the shears and start the azalea pruning season.
This is the best time of year for all kinds of azalea pruning — from light shearing and maintenance clips to fairly aggressive renovation work. Azaleas are highly prune-able with adventitious buds on the entirety of their stems, even into old wood. This means they will break new growth from practically any cut. So now is the time of year for almost every kind of pruning - just after flowering. For lighter maintenance pruning, it gives the plants time to produce new growth and set flower buds for the following season. For harder cuts into older wood, it allows fresh growth time to harden off before winter. It also has the advantage of clipping off the faded flowers that look like little clumps of wet brown tissue paper, making way for fresh new green growth. So , time to act. I try to give myself the window of Mother's Day - July 4 to have all my azalea work completed.
First things first: Do They Actually Need Pruning?
Many azaleas do not need pruning every year. If you are still growing into a larger size or liking loose and natural, by all means, leave them be. You might find yourself removing spent flowers by hand snapping out deadwood and done. Natural azalea habit is often loose, layered, slightly irregular, especially in woodland settings. There are however, other styles and situations. In Japanese style gardens azaleas are tightly controlled and clipped into tamamono or o-karikomi shapes. Azaleas can be hedged for appropriate circumstances. Then there are the concerns of scale and views. So, the first order of business is to assess what your pruning goals actually are before even picking up the shears, secateurs, or a (gasp) pruning saw.
Timing Matters
For all azaleas, flower buds are produced on growth made after this year’s blooms, the buds form later in summer/fall. If you are late to the game, pruning removes these buds and you will lose next spring's flowering. The practical rule -- pruning right after flowering is generally safest.
That said, things don't always go according to plan and sometimes practical realities matter more than perfect timing. Azaleas, particularly established ones, are pretty tough cookies and can take more than you might expect. My alarms would be going off if significant pruning was going on after Labor Day and before Valentine's. If the situation absolutely requires, pruning can go on with the understanding that there will be no or very limited spring flowering and risks of slower recovery
Here may be the good place to mention 'reblooming' azalea varieties. These relatively new hybrids are touted as twice blooming - once in spring and again in autumn. For so many reasons, I am not a fan. I prefer to call them 'half blooming' azaleas...never fully in bloom, they fire off just a little in the spring and just a little in the autumn. Pruning at any time removes flowering. Ugh. I'm not saying 'don't', just managing expectations and now I'll shut up about it!
Techniques
This is a difficult section to write about! It feels ponderous to try and explain in writing because pruning is so physical and observational. If you could be with me and the team in the gardens at this time of year, for a day or 3 of pruning, you could get the gist (and we could use the help)! I'll start with tools to gather. Secateurs, shears, if there is really renovation to do, a pruning saw is a must. If I am doing a lot of or big pruning or any kind of hedging i am not against a set of electric clippers.
You can start off by looking at an individual or stand of shrubs and deciding on a plan of attack. Will I be reducing to see over or put back? Is there one inside stem that wants to be removed? Am I going for natural or formal? Cloud pruned (see TWIG boxwood discussion) or hedged?
With a plan in mind - get to it. I tend to start with shears. Just as with boxwood pruning I clip a bit at a time working towards a size and shape I am going for. If this is something I have been doing for repeated seasons, most of the active growth becomes concentrated on the outer surface where previous cuts were made, so occasionally snipping out a densely grown stem to open a kind of skylight into the interior of the plant is a good practice. This is also a great time to do any dead wooding and removal of troublesome crossing or complicating branches. I'm anticipating 4- 6" on new growth this coming season, so keeping that in mind as I get things back to a size, shape and scale.
If you are dealing with azaleas that are seriously over grown, it may be time for renovation. Large old azaleas can be significantly reduced. at this time of year, you can cut them back extraordinarily hard and and expect them to come back up with some presence by October. My strategy for this kind of pruning is to first identify the oldest trunks and using a pruning saw, cut them back to some 8-10" below where I want the top of their new shape to land. Secondly, I go back through and clip the remaining branching just above these bare trunks, to invite fresher new surface growth (these smaller branches will rebound faster than the old wood). For full recovery from renovation, you might expect 2 complete growing seasons, but if the plants are healthy, they will probably not be unsightly by autumn, and you might even get some springtime flowering next season.
Spa Day
Once I've gotten your pruning work done - and the (sometimes significant) cleanup completed, this is a time I like to try and do one last thing, kind of an extra 'spa treatment' for the newly manicured azaleas. Maybe a bit of fertilizing - if you've got some Hollytone on hand -- I do most of my azalea fertilizing in the late winter/early spring before bloom -- but a little extra now is totally ok. Perhaps you've got some fresh harvest compost that will be easy to toss around now that the plants are tight, and all cleared out underneath. Finally, I've found this is a great time for a spray of light horticultural oil - I mix in a bit of liquid seaweed because I'm fancy like that. All this just a little extra to get things off to a good new start.
In Closing
Now I am going out to do a little bit of azalea pruning along my front walkway. Two azaleas, 'Hardy Gardenia,' have been growing there for years and need to be managed a bit for size. I tend to like tamamono pruning guidelines for them. I'll add a couple of pictures here, and hope you will add yours to 'The Gardener's Stream' and bring along any questions to 'Office Hours' next week!
