Deadheading the spent flowers on a rhododendron tends to focus the energy of the plant towards new flower production and general plant health. It also improves the sight of the plant when not in bloom.
How?
To deadhead, use your fingers and gently rock the base of the spent flower truss back and forth until it separates from the plant. That’s it. Now you can either toss the spent bloom under the shrub for mulch or discard on the compost heap. Your fingers might get a bit sticky from the residue but that’s part of the fun of gardening.
When?
I tend to deadhead my rhodi’s in the evening after I’ve worked all day in the garden and I’m strolling around to admire my work. I usually stop when it gets dark and that’s how I know it’s dinner time.
After the blooms are spent it is beneficial to deadhead your rhododendron
Notched leaves on your rhododendrons are caused by a variety of species of weevils. The adult forms of the weevil tend to feed at night during the springtime when you’re resting after a hard day in the garden. The damage will not kill your plant, just cause unsightly notching on the leaves. Of course, the leaves being evergreen will be around awhile to annoy you.
These notches on the Rhododendron leaf was caused by a weevil
• Hand pluck the critters.
One method of control is to go out to your garden in the evening with your flashlight and pluck the weevils from underneath the rhodi leaves and toss them into a bucket of water. This never appealed to me.
• Spray with systemic insecticide.
Another, more toxic method is to spray with a systemic insecticide, like Orthene. Make sure to follow the instructions on the label. Soak the leaves, both top and bottom as well as the soil underneath to get the best control.
• Accept imperfection.
The third method is to allow for a measure of acceptance of the notches and let nature take its course. Your neighbors will either respect your concern for the environment or talk about your lack of concern for aesthetics.
Generally speaking, cultural requirements are less “demanding” for lepidote (small-leaf) rhododendron and azaleas, both evergreen and deciduous. They tolerate, and to some extent require, more sun than elepidotes, and azaleas will also tolerate less well-drained soil. In all other respects, the general guidelines outlined above apply to all plants in this family.
Site Selection
Rhododendrons prefer a site that provides afternoon shade, some protection from wind, good drainage and air circulation. Sloping terrain is also a decided advantage.
Soil
Well-drained soil is a must. Use raised beds to plant on top of poorly drained soils. Ideally, soil should be acid (ph 4.5 – 6.0) and high in organic matter. Pine bark, coarse sphagnum peat moss, composted wood chips and other such materials can be worked into the soil to improve organic matter content and soil drainage. Incorporate a few handfuls of super phosphate (0-20-0) in the mix to stimulate root growth.
Planting
Container plant root balls must be sufficiently disturbed so that roots extend out from the ball. The planting hole should be wide but shallow. Loosen and amend soil only 8 – 10 ” deep so that the root ball sits on solid ground to prevent sinking. Plant only as deep as the top of the root ball with no soil on top of the ball. Do not pack soil tightly around the plant, as tender roots will be destroyed. Mulch 3″ deep and water thoroughly.
Rhododendron Planting Diagram
Mulching
Mulch with 3″ of pine bark, pine needles, oak leaves, composted wood chips or other loose airy material. Do not use maple leaves, grass clippings or other materials that pack down.
Loading mulch for placing under shrubs
Fertilizing
If plants hold good green color and grow well, no fertilizer is needed. Rhododendrons are not heavy “feeders”. A soil test can determine what elements are deficient if plants do not perform well. When necessary, apply a fertilizer formulated for acid loving plants in late winter or early spring. Don’t fertilize after June 1st.
Watering
Proper watering is an important after care practice, especially for the first several years as plants become established. Keep the soil moist but not wet. Water deeply, (apply 1″) in the absence of equivalent rainfall. Don’t water again until the soil starts to dry out. Afternoon wilting of new growth is normal. If leaves become turgid a few hours after sundown, no additional water is needed. Water requirements diminish in late summer and early fall as new growth hardens up for winter. Plants should, however, be watered going into winter following a dry fall.
This is part of an outline of a ten minute talk I gave to the Centerport Garden Club on November 9, 2010
HOW ARE RHODODENDRONS CLASSIFIED?
Rhododendrons are classified into two major groups, lepidote and elepidote?
Elepidotes are large leaved rhododendrons. They are the type of shrub that most individuals would associate as being a rhododendron. They do not have scales located on the underside of the leaves. Plants tend to be very large in their maturity.
Elipidote Rhododendrons have big leaves
Lepidote rhododendrons have smaller leaves and are usually low growing or dwarfs. They usually bloom earlier in the spring than the larger leaved elepidotes.
Lepidote Rhododendrons have small leaves
WHAT IS THE DIFFERENCE BETWEEN AZALEAS AND RHODODENDRONS?
Rhododendrons have 10 stamens, 2 per lobe
All azaleas are rhododendrons but not all rhododendrons are azaleas.
True rhododendrons have 10 or more stamens which is 2 per lobe. Azaleas usually have 5 stamens or 1 per lobe. Azaleas have 5 lobes in a flower
Azaleas tend to have appressed hairs which are hair parallel to the surface of the leaf. This is particularly true along the midrib on the underside of the leaf. It is easily seen in “evergreen” azaleas.
True rhododendrons instead of hair are often scaly or have small dots on the under side of the leaf.
Azalea leaves are never dotted with scales and are frequently pubescent.
Many azaleas are deciduous.
True rhodi’s are usually evergreen with the exceptions of R. mucronulatum and R. dauricum.
Azaleas have tubular funnel or funnel shaped flowers. Rhodi flowers tend to be bell-shaped.
This is an outline of a ten minute talk I gave to the Centerport Garden Club on November 9, 2010
Botanical Classification
Rhododendrons and azaleas belong to the genus Rhododendron of the heath family (Ericaceae).
The heath family includes the heaths and heathers, blueberries, mountain laurels and several other ornamental plant groups. Most members of this family require acid soil and good drainage.
This is a selection of the Rhododendrons submitted to the judging of the Spring Flower Show at the NY Chapter of the American Rhododendron Society at Planting Fields Arboretum
Where are Rhododendron’s from?
Some are native to the US.
The British became the first explorers to seek out new additions.
Collecting has brought plants, seeds & cuttings from Japan, China & the Himalayas.
New species are still being collected in central China.
In the 1800’s they were so expensive & were considered a rich person’s plant. They appeared on estates and in arboretums.
Most of the Rhodi’s we know today are hybrids created from the parents of the plants collected by these plant explorers.
Azaleas blooming in May in my garden in Northport NY
Common Types
Large leaf evergreen Rhodi’s: Great for screening and as a backdrop behind the flower garden, Catawbiense, English Roseum, Scintillation, Maximum
Small leaf evergreen Rhodi’s: some sport beautiful mahogany leaves during the winter months, Aglo, Dora Amateus, Mary Fleming, the PJM’s
Yakushimanum hybrids: usually 3’wx3’h with woolly indumentum on dark green leaves. Have wonderful winter interest, Crete, Fantastica, Ken Janek, Percy Wiseman, Prince & Princess
Species Rhododendrons, can present well in a mixed flower, shrub border. There is a species rhododendron garden in DC.
Azaleas-Evergreen: Michael Dirr begins his Azalea Cultivar & Hybrid Group section with:
“In some respects, it is paralyzingly frightening to attempt to present the cultivars of azaleas.”
There are so many but you can begin to study them realizing that some are named for their hybridizers: i.e. Girard Hybrids, Glen Dale Hybrids, Polly Hill’s North Tisbury Hybrids. Others by their location: i.e. Linwood Hybrids, Karume Hybrids of Japan.
Today the sun is shining on the beauty of my garden after the blizzard of February 10th, 2010.
View from my deck after the beautiful snow storm
I haven’t been out yet since I’m leaving all the shoveling to my son Michael and hubby Dave. But I ventured to take the screens out of some upstairs windows and shot some photos and video of the heavily snow laden branches.
It seems from my perspective so far that the only major damage is the loss, yet again, of the top of the American Holly, (Ilex opaca). I don’t remember what year it was but it happened once before over a 15 years ago. The central apex broke at the time from another snowstorm but grew back with a double lead. I don’t knew yet whether I’ve lost just one or both.
I made a short, one-minute video of the garden as it looks this morning before the wind picks up and blows all the heavy snow from the branches. It will be fun to watch the garden perk up during the day as the snow begins to rearrange itself.
Four O’Clocks were my first introduction to growing plants from seed. Uncle Teddy took me by the hand at his home in Schenectady and introduced me, the kid from Brooklyn, to gardening. I can still smell the soil as we dropped the seeds of Four O’Clocks into the ground he taught me to prepare. Four O’Clocks weren’t the only things growing in his garden, so was I.
The Kansas Peonies I grown in my garden was a Mother’s Day present from my son Chris. I have so many gifts he’s given to me over our many years together but I still cherish the bright pink of these robust plants each year as they bloom for me right in season. They return each Mother’s Day, expanding and adding to their beauty, as does he.
One year for my September birthday, my son, Michael came swooping in proudly bestowing upon me a stripling of a Japanese Maple. Still dangling was the $9.99 tag placed on it from Home Depot. Now this mature specimen holds court as a central focal point in my front garden.
A bouquet of Zinnias comes into my hands each year when my husband Dave buys them from the gardener with a stand up the street from us. The grin on his boyish face as he hands them to me with love is matched only by the riotous colors of the single and double flowers grouped tightly in his hands.
On Mother’s Day this year my grandson C.J. bounced up to greet me with a pot full of poppies. He shares my garden with me and helps to bring my attention to all the wonderful colors and shapes he finds there for fear I might miss them. These poppies are pink he told me and reminded me that we need to photograph everything so we’ll remember how they looked.
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