Rhododendrons are popular among gardeners with their evergreen shrubbery and early blooms.
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Planting, Growing, and Pruning Rhododendrons and Azaleas
Planting
Most large-leafed varieties require dappled shade; avoid deep shade or full sun. A sunny spot that receives a few hours of shade is perfect. See regional guidelines below.
Soil should be well-drained, humus-rich, moist, and acidic (pH 4.5鈥6).
Azaleas and rhododendrons have shallow root systems and need moist soil and mulch to keep them from drying out. Amend planting areas with compost, peat moss, or a substitute, only if your soil is poor. Learn more about soil amendments and preparing soil for planting.
鈫 Not sure which hardiness zone you鈥檙e in? See the USDA map.
Planting in Cold or Temperate Regions (Zones 3 to 6)
- Plant in full sun to increase flowers and avoid mildew problems. Shrubs need a minimum of 6 hours of full sun daily.
- Plant on the sheltered side of a windbreak. If subjected to cold, dry winds, their leaves and buds dry out and die, especially during winter winds.
Planting in Warm or Hot Regions (Zones 7 to 11)
- Plant in a site that receives afternoon shade, especially in hot areas. In tropical zones, azaleas will bloom in full shade.
How to Plant Rhododendron & Azaleas
- Plant in spring or early fall.
- Space plants 2 to 6 feet apart, depending on their estimated mature size. Dig a hole as deep as the root ball and about twice as wide.
- Set new plants so that their top roots are at soil level or slightly below. If you plant them any deeper, the roots and trunks may rot.
- Fill the hole half full with soil, then water it well to settle the soil before filling it with the remainder of the soil.
Growing
How to Care for Rhododendron & Azaleas
- Mulch plants every spring with 2 to 5 inches of pine bark chips or pine needles to protect shallow roots and retain soil moisture. A lack of water reduces flower bud formation. Read more about using mulch.
- Tip: A common mistake is to create a so-called 鈥渕ulch volcano,鈥 where mulch is piled heavily around the trunk of the shrub. In fact, this can keep the trunk too wet and encourage rot. Always leave a few inches around the trunk free of mulch.
- See our guide to using mulch.
- Fertilize azaleas and rhododendrons sparingly and only when flower buds swell in the early spring, even if they are fall bloomers. Heavy applications of fertilizer will burn the plants鈥 roots.
- Water plants during the summer if rainfall is less than 1 inch per week.
- After flowering, deadhead where practical, to promote vegetative growth rather than seed production. Remove dead flowers from rhododendrons carefully; next year鈥檚 buds are just under the old heads and will start to develop shortly after flowering.
- Azaleas and rhododendrons may be transplanted at any time during the growing season, but they transplant most successfully during fall or early spring when they are dormant and temperatures are cool.
Winter Care for Rhododendrons
Rhododendrons are shallow-rooted plants; in cold regions, apply several inches of organic mulch around the base. In regions with severe winters, consider wrapping evergreen rhododendrons with burlap in the fall. Cold, dry winds will cause too much moisture evaporation from the leaves, which will wither and die. To help them recover from cold snaps, deeply water rhododendrons if there are warmer days. In the spring, prune out any dead or damaged branches and leaves.
Pruning Rhododendron & Azaleas
- In general, do not prune spring-flowering shrubs such as azaleas and rhododendrons. If you need to reduce height, prune after flowering in the spring.
- Otherwise, just remove dead, damaged, or diseased branches at any time of year.
- On young and old plants, simply snap off spent flower stalks by bending them over until they break away from their stems. Be careful not to damage growth buds at the base of each flower stalk.
Catherine Boeckmann
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I cover my azalea bushes in the spring if we have a late frost. For the first time ever, one of them has bloomed this fall. Do I need to cover it in the fall when it frosts, if it has blooms? It's about 2 feet tall, and is covered in beautiful pink blooms. I live in TN and we have had some very warm days in Sept and Oct. We had about a week of freezing night temps in the last month, and I covered it every night. We are expecting several night of freezing temps next week. One of the covers blew off the other azalea bush in the spring of 2016 and it didn't bloom this year at all.... has a few green leaves is all. I don't want to lose the other one, it is the last bush that I have that was my dad's...
I just planted my first rhododendron this spring. Read about the soil care and followed that. Kept end up with watering, maybe not enough but it looked good. Bloomed this season but there are no buds on it now. Questioning if it received enough sunlight? No direct sunlight at all in its location, thinking this might be the issue?
Hi Kathleen,
Rhododendrons are spring-blooming only, so it’s completely normal for there to be no blooms at this time of year.
I started 5 new plants by weighing the branches down than covering branch with dirt. After 6 or 8 months the branches established roots and I cut the branch from mother rhododendron and planted the cuttings in different locations. The plants are now 6 ft tall but do not produce many blooms. Some years 1 or 2 others none. What should I do to get them to bloom
Do you know what variety of rhododendron you have? If you do, then you can figure out if they’re of a variety that prefers more shade or more sun. It sounds like your plants are growing quite well, though, so it may be the case that they simply need more time to establish themselves. Rhododendrons can take several years to truly settle in, at which point you should see better blooms. Another thing to check is that they are not drying out too much. Adding mulch (but leaving space around the trunk to prevent rot) can help with that.
Inherited it, as a tree, 35 yrs ago. Too tall to nip off the buds.
Just cut out lots of dead branches trailing lower down.
Can I prune it somehow to reduce the height or just leave it to do its thing?
I accidentally broke off a major branch of my favorite rhody while laying mulch down. I put it in a bucket of water thinking I may be able to save it to create a new plant. It has been in the bucket now for almost a week and looks lovely so far. Is this possible? If so, do I leave it in water for a while then try to plant it into a container? I think I am wishing for the best here. Any comments back are welcomed. Thank you.
You might be able to save it, Susie: You will need rooting powder, available at most nurseries and supply stores. Trim the broken end by removing a couple inches of bark. Dampen the end (it’s good that the piece is in water!) and dip the end into the rooting powder, then make a hole in a container of moistened potting medium (or 1/2 portion peat, 1/4 portion perlite, and 1/4 portion sand), and plant it. Firm the 鈥渟oil鈥 around the plant. Put the entire thing into a clean plastic bag, secure it at the top and set it in an area that gets light but not direct sun. Look into the bag occasionally to be sure that mold or the like has not set it (if so, spray it with a fungicide). The rooting process will take three to four months or so. After a couple of months you can gently nudge the plant to see if it seems to have 鈥済rabbed鈥 the soil (with roots!). Water as needed when you take a peek.
I have an old rhododendron that, frankly, has grown too big for the spot that it is in. For many years it bloomed satisfactorily but last year the blooms were sparse and this year none at all. I looked at the possibility of pruning it but the leaves are all on the outside and pruning would leave nothing but bare wood. But then I noticed some new breaks at the base. So could I remove all of the old branches and let the new breaks develop into a "new" plant? Also, what is your advice about fertilizing in this situation. Thanks for the help.
There are several reasons why plants do not bloom. Re rhodos in particular:
鈥 were they nipped by frost?
鈥 are they too dry/lacking moisture?
鈥 is it getting enough light? Rhodos need a balance of light and shade (there is no specific formula) and cool feet, which is to say they do not like a place where the ground under them gets too warm.
We suggest you also read the care and pruning tips above. You could prune this tree down to the new growth but it behooves you to consider the previous and above before doing anything drastic…if you want to keep the plant. Of course you could prune it a little.
As for fertilizer, these plants like acidic soil; check your soil’s pH. It can change over time and perhaps has slipped out of range (see above). Amend as needed. And, spread add aged manure under it (wide, not just at the stem, so it affects the shallow roots) in the fall or not at all鈥攁s the saying goes.
We hope this helps!
