Encouraging lush foliage with a rhodo?

joel_bc(z6 BC)August 2, 2007

Assuming that: a) you have a well chosen variety of rhododendron for your climate and for the spot you've planted it in, and b) you got a good hardy specimen from the nursery - what is the best way to encourage lush foliar growth and secondary and tertiary branches?

Is the secret soil pH, pruning, or nutrient supply (feeding)? Or...?

I've had a few rhododendrons, a couple of which had a bit of a life before deer ate them down to sticks. So I do have some experience. Right now, I'm more interested in a good start to the structure and healthy green growth than I am in blooms... although I appreciate the blooms when they're there. But give me advice about shoots and leaves, please. Thanks.

Joel

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morz8(Washington Coast Z8b)

Joel, healthy happy rhododendrons are those planted in aerated soil (structure loose enough that air can enter spaces between particles as water drains out), and that means high in organic content. Acid soil, cool and moist with shelter from wind and excessive sun.

Given those conditions, there is seldom a need to fertilize. Nitrogen will promote foliage growth (active growth occurs in Spring) but it's not a good plan to try forcing these shrubs with supplemental 'feeding' and especially not now (August) in a Z6.

So your answer, once your shrubs have been correctly sited, is pruning, or better yet pinching. Some rhododendrons are just naturally leggy while others branch readily and grow into compact bushy forms. By pinching or breaking out leaf buds in the first few years after planting, you can shape potentially leggy plants into a more well balanced shape.

As growth buds begin to elongate in Spring, pinch out the terminal buds. A plant hormone is produced by leaf buds which inhibits development of dormant buds along the stem (flower buds don't produce the hormone - leave those fat blunt nosed flower buds alone:)).

If you start when the plant is young and keep it up about three years, you may only then need to occasionally pinch leaf buds which would grow out to unbalance the plant. As healthy rhododendrons mature, they being to produce more terminal flower buds and less terminal leaf buds and will require less of your attention to shaping.

    Bookmark   August 3, 2007 at 12:31AM
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Birdsong72(7/Northshore NJ)

Good post morz. Right on the money.

And a big hello to the Pacific NW. I have friends on Whidbey and miss being out there at this time of the year.

It's hot, hazy & humid this past week, with supplemental watering being the case (we missed last nite's sporadic downpours)....

    Bookmark   August 4, 2007 at 1:31PM
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