Rhododendron and
Azalea News

Plant Tips

For beginners…

Mary Palmer, North Island Chapter writes...there are easily a hundred good varieties of rhodies in just about every color and size that you could wish.  Rhodies are acid lovers, which means they will do well almost anywhere on the coastal regions of Vancouver Island…and, without doubt, would be applicable elsewhere for the most part.

• Rhodies like a fibrous loamy soil…accomplished by adding at least 60% coarse peat moss or bark mulch. In a clay soil, add 50% coarse peat or bark mulch and 10% sand.

• Add a good rhodie fertilizer to your mixture.  When using sawdust or bark mulch, sprinkle a little ammonium sulphate around each plant.  

• Some rhododendrons grow in full sun, most prefer semi-shade, blooming in April, May, and June.  And some will bloom as early as January while others wait until July or August.

• Rhodies are shallow-rooted, with their tiny feeder roots located in the top four inches of soil.  They appreciate a mulch of old rotted wood, coarse peat moss, or bark mulch.  Do not dig around the plant when weeding or cultivating.

• If leaves lack color, give plant a small feed of ammonium sulphate in May…or Epsom salts any time.

• Feed the plant when finished flowering, spread fertilizer around the plant, soaking it in well.

• Foliage may be fed with liquid fish fertilizer, but this is not enough to set buds for the following year.  Use a good rhododendron fertilizer with trace elements, and do not feed after the end of June.  

• Many small-leaved rhodies resent any fertilizer…for these chopped leaf-mold and compost is all that is needed.  Try this method…you’ll like it!

Transplanting rhododendrons

A beginner’s question often is: in transplanting a rhododendron, is it important to retain as many roots as possible?  And, how far do the roots extend from the plant stem?

Answer: In general, roots extend beyond their stems by, at least, the height of the plant.  However, rhododendrons have a fine, compact root system, which usually extends out to the drip line (the outer-most leaves).  In depth, the majority of the roots are in the top eight inches, with the feeder roots in the top two inches.  When transplanting rhododendrons, it is not necessary to retain all the roots…but try to keep as many as possible without the root ball falling apart.

Slugs…get rid of them

Believe it or not…slugs love to eat cardboard!  Cut 6" squares of cereal boxes (Special K!), which stay quite firm in wet weather, and place squares near plants the slugs are feasting on.  They will congregate under the cardboard, and are then easy to scrape off.

"Dead spots” in the lawn

Find “dead spots” in your lawn, sprout a few grass seeds on a damp, used teabag, then plant it in the lawn when the weather allows.

Old wood…new wood

“Flowering on old wood” refers to the age of twigs on which flowers bloom each year.  Old wood is any twig, branch, or stem that was produced during a previous growing season.  In other words, when examining a plant in early spring, old wood would be that produced the summer before or earlier.

Some plants produce flower buds in mid-to-late summer, i.e. rhodos.  These buds winter over in a dormant condition, then bloom the next spring.  This group includes: Forsythias, Hydrangea macrophylla, and various Hollies.

Other plants produce flower buds during the spring flush of growth and bloom as soon as mature.  Since these flowers are on brand new twigs, they are said to be “blooming on new wood.”  Buddleias, for instance.

KNOW your plants before pruning!

• Old wood…prune as soon as flowering finishes, giving the plant time to generate buds for the next year.
• New wood…prune severely in late winter.  Any rhodo pruned severely in late winter will not produce flowers that year.

From Fine Gardening, July-August 2002, intended to give a few added thoughts to make gardening more fun.

Black buds

Is there a solution?  Hank Helm from the Kitsap Chapter writes that he had some black buds on some on his plants.  He thinks they may be Bud Blast, pychostyanus azaleae, a sap-eating fungus which attacks the buds.  The buds turn gray-black and can stay on the plant for two to three years.  Close inspection reveals fruiting bodies of the fungus protruding from the buds.

It is not known for sure, but it is believed, that the leafhopper facilitates the spread of this disease.  The leafhopper lays over-wintering eggs in the slits of the bud, which allows entrance of the fungus.

The best control is to pick off the buds and destroy them.  Spraying with a contact insecticide, beginning in August and continuing into the fall, can control the leafhoppers…and thus, the disease.  Bud Blast does not seem to attack all plants. In fact, there are only a few, usually with R. catwabiense in their background, that are affected.

From the Rhodie Compost Pile, Ozark Chapter’s Spring 2003 Newsletter

There's an old saying:

• Give a man an inch, and he wants a foot, and he wants a yard;
• Give a man a yard, and he wants a rhodie garden!”

In other words, what this is trying to say is this:

• No matter how much we get, it’s only a matter of time before it’s not enough!
• No matter how good things get, people will still complain.

So let’s take a look into the crystal ball and listen to some of those FUTURE COMPLAINTS.

• Over 200 years ago people loved their small bloom rhodie species.

Now people complain about needing more varieties when there are at least 5,000 to chose from, some with 5-in. flowers in trusses over a foot tall, and some like the Encores that bloom many times a year.

• Fifty years from now what will people be saying?

“These genetically-engineered rhodies that bloom in fourteen different colors only bloom 325 days a year.  It’s time to dig them up and get something better!”  Get it.

• Rhodie farmers used to complain of working 10-hour days, 6 days a week maintaining their crops.

Now people complain about working 8-hour days, 5 days a week.

• In the future:

These two-day workweeks are killing me!  Need some time off.  You just had Valentine’s Day off, and Groundhog Day off, and even St. Patrick’s Day, too.  Yeah, but you were made to come in on Millard Fillmore’s birthday to push the water time button, and am still tired from that.

• People used to gripe about watering by hand.

Now they gripe about their automatic sprinkler system not watering evenly.  Some too wet…some too dry.

• In the future, their automatic sensors control watering and feeding on each individual plant and they complain the plants grow so fast and never die, and they have no room for trying any new varieties.

• People used to complain about how hard it was to chop firewood to heat their house.  Now people complain about $250 heating bills.

In the future because of global warming: “This 10-dollar heating bill is just ridiculous.  How can we afford that!”

• People used to complain that all of their rhodies died in the hot Midwest summers.

Now they complain that they can’t grow yellow rhodies in hot summers.

• In the future: “These new hybrid rhodies never need any watering, fertilizing, deadheading, or pruning…so am not getting any organic matter at all to put in “The Rhodie Compost Pile!”

Coppicing means…

Plants successful to coppicing…

Cutting the whole plant back to 3-6 in. above ground…avoid doing it to year-old plants…but it’s a great way to rejuvenate an old bush with dead wood in the center.  Pile lots of compost on the plant after coppicing to encourage new growth. This is a good way to keep shrubs in the perennial border within bounds. If variegated, the new leaves will have brighter color, with flowers larger, more colorful…and more of them!

Include: Belia, Buddleia, Callicarpa, Caryopteris, Catalpa, Cotinus, Hibiscus syriacus, Hydrangea paniculata, Pyracantha, Rosa rugosa, Salix (willows of all kinds), Tamarix, Vitex agnuscastu.

Want some visual punch? 

Colleen Slater of Fraser South Chapter wants to expose a plant.  Not exactly a companion as such for most rhododendrons…but many gardens have a sunny place that could use a bit of “visual punch,” and the yucca could do just that!  Also called Adam’s Needle or dagger plants, these names are obviously derived from the stiff sharp-tipped leaves that are usual among the genus.  Of the 40 or so species native to North and Central America, only a few from the Southeast U.S.A. are suitable for the Canadian area…but these do very well in proper settings.  Any average soil that drains well in a full south or western exposure is fine…and, if the soil is a bit heavy…incorporate pumice or grit of some sort to improve aeration.  Note of caution: leave tips are REALLY sharp and will cause injury if planted too close to walks or where children play.

The clumps are slow to increase in size, but could reach 4 or 5 feet across in some time.  They increase by sucker that can be easily removed and relocate whether showing foliage or just “toes,” and just digging around the base will expose them to be sliced away with a sharp knife without digging up the whole plant.

In past times, various yuccas were much more than just ornamental shrubs…they provided leaf fibers for ropes, baskets and mats; food from flowers and fruits; soap from the stems and roots, and party drinks from the fermented fruit.

Up ‘til fairly recently, only green forms were readily available, either Y. filamentosa…with prominent curling threads on the edges of stiffly upright dark evergreen leaves; or Y. flaccida and its selection ‘Ivory Tower’…with more arching blue-green leaves with only a few threads.  The blooms on both are stately panicles of bellflowers on tall stalks above the leaves in summer, all in cream or slightly green-tinged.  Now offered for sale are some striking variegated forms with gold or white patterning on the leaves.  These are generally slower growing a bit shyer to bloom, but make up for in foliage effect.  Look for such names as: 'Garland Gold', 'Bright Edge', 'Variegata', 'Golden Sword', and 'Color Guard'.

Try to plan the placement of these with some care:

• They make a very strong tropical statement and can be overdone if used in conjunction with too many other vertical accents.
• They combine well with mounding shrubs, such as Helianthemum, Brachyglottis, Santolina, Cistus, or Cotoneaster…but
• Let the yuca stand proud without overcrowding.

In truth, I may be tempted to try to combine one or two of the dwarf alpine rhodos in the same area, or even some of the older ‘ironclad’ varieties as background.  Given that these yucca species are not from extremely arid climates, with adequate drainage they could well tolerate conditions that some of the more resilient rhodos can thrive in also.

So make a liar out of me…plant yuccas and rhododendrons together and make them like each other!  Happy Planting!!

Lovers of Henry David Thoreau

Submitted by Ed Metcalfe from the Peace Arch Chapter...

One pleasant morning after a cold night, February 24, 1850, having gone to Flint’s Pond to spend the day, I noticed with surprise, that when I struck the ice with the head of my axe, it resounded like a gong for many rods around, or as if I had struck on a tight drumhead. The pond began to boom about an hour after sunrise, when it felt the influence of the sun’s rays slanted upon it from over the hills; it stretched itself and yawned like a waking man with a gradually increasing tumult, which was kept up three or four hours. It took a short siesta at noon, and boomed once more toward night, as the sun was withdrawing his influence.

Understanding rhododendron cold hardiness…

Ted Van Venn, Portland Chapter, writes: the following points, which first appeared in the ARS’ Journal, Fall 1995, is worth printing again…for everyone!

Age.  It takes about five years for a rhododendron to reach full maturity for hardiness.  Young plants need extra protection.

Transplanting.  Mature plants that have been moved will need added protection until established.

Variety.  Some varieties are slower to harden in the fall.  Damage may occur when subfreezing weather comes suddenly, without the benefit of light frosts.

Garden location.  Each garden has microclimates.  Temperature may vary within a garden as much as five degrees.  When the hardiness of a plant is marginal, choose the best garden location, using the following criteria:

• Choose areas of good air drainage; keep away from frost pockets.
• High, filtered shade or northern exposures protect plants rapid temperature changes.
• Mulch plants after ground has cooled.

Raising rhododendrons and azaleas from seed

Raising rhododendrons and azaleas from seed is easy.  First, fill a pot or suitable container with some standard rhododendron potting mixture, such as equal parts peat moss, sand, and perlite.

The medium should be moist…but not wet.  Firm the surface lightly and sprinkle the seeds over the top.  Place the pot inside a clear plastic bag to make a mini-greenhouse, and put the container under some fluorescent lights or in a bright window that doesn’t get too much direct sun.

Seeds will germinate in three to four weeks and should require no additional care until spring when seedlings can be transplanted into individual pots.

Good news: Rhododendrons can bloom in three to four years from seed, and azaleas bloom even sooner!

Tasks and chores for spring - great advice!

Paul Lawry from Nanaimo Chapter provides valuable guidelines for all gardeners.  Listen to his counsel, take notes, and mark your own checklist below:

Even though it may still be cold, damp and miserable outdoors, an occasional dose of sunshine could certainly put the gardening bug into you.  With a little luck, Mother Nature will send a few blossoms your way this month.  We are now at a time when we can no longer put off those garden projects, waiting for a nice day.

• Don't be caught off guard though, winter is far from being over!  If exceptionally cold weather is forecast, provide protection to early flowering or tender plants by covering them with some type of cloth material.  Remove the covering as soon as the weather moderates again.
• Deciduous shrubs and trees are still dormant enough to transplant this month, once the buds have begun to swell, it will be too late.
• Trees, which weren’t fed last fall, should be deep fed by punching a series of 1-2 in.  Holes two feet apart around the drip line and filled with an appropriate food.  A mulch of well-composted manure is also an excellent treat for your tree.
• Fertilize shrubs and evergreens if this wasn’t done in February.  Use an acid type rhododendron fertilizer to feed evergreens, conifers, broad leaf evergreens, rhododendrons, azaleas, and camellias.  Use an all-purpose fertilizer to feed roses and other deciduous trees and shrubs. If you use dry type fertilizers, be sure to water it in thoroughly.
• Prune your summer flowering shrubs NOW… but be aware that spring bloomers have already produced their buds last fall, and pruning them now will result in the loss of flowers.  Forsythia, quince, spirea, and other early spring flowering shrubs should be pruned a little later, after they have finished flowering.  Prune to improve the shape of the plant, as well as to open up the center of the plant to good air circulation and sun exposure.  Always start your pruning by removing all dead, decayed or broken branches.
• It's a good time to stroll around and trim back any branches that were damaged by the ravages of winter.
• If you haven't yet applied your dormant fruit spray, DO IT NOW!
• There often is a strong temptation to start removing winter mulches from your flowerbeds…WAIT!  Pull the mulch off gradually as the plants show signs of new growth.  Remember: the purpose of winter mulch is to act as a protector from sudden changes of temperature and chilling winds…so keep mind that it is still winter.  Acclimatize your plants by removing the mulch over a periods of days, allowing the light and air to reach the new growth slowly.  It is much better to remove the mulch a little later than to remove it too early.

Paul comments further that most of us have other plants to enhance the beauty of rhododendrons, here are a few more things to think about…

• Roses can be pruned now.  Severe pruning results in nicer, long-stemmed flowers, and more compact bushiness.  Begin to spray roses for black-spot.  Feed roses.
• Plant daylilies, bleeding hearts, and plantain lilies this month.
• Deciduous vines such as honeysuckle should be pruned and shaped.
• Divide and transplant summer blooming perennials and fertilize established ones as soon as new growth appears.
• Check your stored plants such as fuchsias and geraniums, and if they are shriveled water them lightly.
• Summer flowering bulbs may try to start into growth if they are subjected to heat. They should be kept very dry, and stored at 45 degrees F.  If they are shriveling, put them into slightly damp peat moss, but keep them cool!
• If you plan to grow lobelia, ageratum, verbena, petunia, vinca, or other plants from scratch, the seeds should be started indoors in the later part of the month.
• Climbing roses should be thinned out to get rid of last years tangled growth.
• Sow seeds of summer blooming annuals indoor.  Seeds, which were started indoors last month, may be transplanted from the flats into peat pots and given dilute fertilizer.
• Alternating thawing and freezing can tear plant roots and even force the plant right out of its hole. If you notice any plants that have heaved, push them back into the earth, push them back into the earth, and tamp lightly with your foot.
• Remove all dead blooms from bulbs.
• Fertilize any bulbs that have finished blooming with bone meal or bulb booster.

Paul tosses in a few more added points not to forget...

• The most dreaded task of all tasks is…weeding!  BUT it is one that really needs to be accomplished before the weeds have a chance to flower and go to seed.  Remember once the weeds go to seed…you can be fighting that weed seed for up to seven years…or more!  An awful thought!  Most weeds can simply be pulled or cultivated out of the garden while they are young.
• Keep an eye out for aphids (spray off with water) and cutworms (cutworm dust).
• Continue feeding our feathered friends, you'll want them to stick around to help you in insect control when the weather warms again.  AND, clean out all of your birdhouse NOW so that they will be ready when the birds return.
• Did you check your garden tools yet?  Don't wait 'til the spring rush to get your mower back in shape!
• In the event of snow, be sure to shake or brush off the white stuff from the branches of your evergreens and shrubs. 
• It's time to turn the compost pile!

One more thought…

Have a great gardening day!