Plant Tips

Dr. Rhody question...buds or leaves?

Have a question:  I have a nice plant that was purchased last September.  It had what appeared to be very large flower buds.  This Spring those buds opened and leaves emerged! Is it possible for flower buds to change into leaf buds?

- Wondering

no...

The short answer to your query is "no", flower buds do not change to leaf buds. They are always leaf buds. Some of the elepidote species and hybrids have very large buds. It is, indeed, difficult to tell whether the buds is a flower or a leaf.

One indication is the shape of the bud. If it is round, it is usually a flower bud. If the bud has a sharp point, it is usually a leaf.

Those in between are often difficult to distinguish the first year you see them. As you see more and more buds it becomes easier to tell the difference.

- Dr. Rhody

Winter protection of rhododendrons

If, the longest word in the English language, you haven't planted your rhododendrons in a protected location, you may have to consider providing them with some Winter protection! Rhododendrons, particularly large leafed forms, are sensitive to Winter sun as well as winter winds, and if not protected properly, you may have serious damage or lose the plant by Spring.

rhodies need moisture...

Damage to plants is likely to happened if the plant did not receive ample moisture before in the Fall. During the Winter, drying winds and frozen ground deprives plants of their natural moisture intake. The exposed portions of the leaf...usually the central portion when the leaf was curled...may become brown. This may also appear on the edges of some leaves.

To prevent scorch, plants should be well watered in November, especially if rainfall has been sparse; protected from drying winds; mulched well, and given some shade. New plant growth may not have a sufficient amount of time to become woodsy and harden off for the winter. Also, flower buds are the least cold hardy part of the plant.

plants may benefit from anti-desiccant...

Rhododendrons, boxwood, azaleas, hollies, and laurel will benefit from an application of an anti-desiccant, such as Wilt-Pruf. Read and follow all instructions. Spraying should occur in late Fall when temperatures are near 40 degrees F.

If you do not get a change to apply an anti-desiccant, you may want to provide a wind-shield...such as burlap to these shrubs as well as some mulch protect ion around the base of the shrub. Most anti-desiccants are composed of a "waxy" substance that can break down during Winter's thaws necessitating a reapplication.

chicken wire enclosures...

Young plants can be enclosed with chicken wire or dog fencing...and packed loosely with oak leaves. Remove the protection in the Spring as buds start expanding. Mature plants can be mulched with several inches of wood chips at the base. Evergreen boughs can be leaned or tied against plants to limit Winter injury.

try teepee-like structures, too...

A teepee-like structure constructed with three or four evergreen trees or branches with their points forced into the ground and tips tied together provides adequate protection...or use a burlap covering around individual plants. Snow fencing alone or with a polyethylene plastic sheeting attached to it also gives effective wind protection. Cover the plants just before freeze up in the Fall and uncover after all the frost is out of the ground in the Spring.

3 years required protection for young plants...

Winter protection is usually required for up to three years while the new rhododendrons become well established in their new location.

Note: The Connecticut Chapter gave this advice in their newsletter in 2001. It is still important to consider. Most of the United States has been hard hit for the Winter season...and it is still with us. Take note for next year...the editor will!

A bud is a bud...but will it flower?

The Portland Chapter generates the most interesting newsletters and has a column called "Square 1". In their May 2006 newsletter the column posed this question: A bud is a bud...but will it flower?

Here’s the answer. You spied the perfect plant in a sale...so many lovely buds, but no flowers? You might be surprised to find that not all buds are flowers...some are simply growth buds and have only leaves.

growth buds...

Growth buds are, according to Rhododendrons, by John Street...whose father was Gomer Waterer...a namesake for a lovely plant, and great British rhododendron hybridist, a "latent tip of the growing shoot from which the following year's growth and flowers will develop."

flower buds...

Flower buds are dormant flower(s) sheathed in leaves usually formed in late summer and clearly visible throughout the Winter. The search was on...this was a nice description...but simply wasn't much help in describing which was which...and how to see it.

not satisfied...search was on...

After digging around in my library and reading through at least a dozen books, I knew it was time to make a call to a local expert. It's after 9 p.m. and I'm wondering if anyone is home and interested in talking rhododendrons.

Bob MacArthur to the rescue...

I was very relieved to talk with Bob MacArthur who described the differences in about...oh, 30 seconds! Growth buds are more candle-like and the growth is often called a "candle" because of its shape. Flower buds are wider at the base and taper towards the ends...more like the shape of a vase.Now, why did I not remember this?

also look for other problems...

While you are there examining the bud shape, you might want to look for other bud problems that might rob you of that beautiful bloom you had hoped for.

Bud blight symptoms include buds that turn brown and are covered with black bristles. These bristles are really spores from the fungus Briosia azalea. In this case, remove and dispose of the affected buds...burn...no compost!

According to Greer's Guidebook to Available Rhododendrons, species and hybrids, some cultivars will lose buds even if the temperatures are not low enough to damage the bud or cause leaf damage.

Some seedy facts

Now is the fun time. How's that? Many people thoroughly enjoy a cup of hot chocolate, soft music, and reviewing the latest seed catalogs! Each is beautiful in its on right...colorful...excellent descriptions...inviting. Some thoughts!

When perusing seed and plant catalogs, you have probably come across varieties labeled as "F1" or "OP" and wondered what that means.

"F1" hybrids...

"F1" hybrids are created by taking the pollen from the male parts of one pure, inbred plant and transferring it to the female parts of a different pure, inbred plant. The goal is to produced a new variety that is superior to either parent: larger, high-yielding, more disease-resistant, more vigorous, among other criteria. The new variety or offspring is called an "F1" hybrid. Seeds from F1 hybrid plants will not likely breed true for future plants.

"OP"...

On the other hand, varieties labeled "OP"...open pollinated...will grow true to variety name from seeds produced form the plant that you grow yourself. These may be saved and will produced the same plant in future sowings...as long as proper seed-saving procedures are followed. Visit  www.seedsafe.org for detailed seed-saving instructions.

- Thoughts from Whidbey Island Chapter, January 2008

How to prevent and treat powdery mildew

Powdery mildew is very common to the Pacific Northwest and is caused by members of the fungus genus Microsphaera. The disease can affect both hybrid and species rhododendrons. Surprisingly, the symptoms are different for rhodies than for many plants. Specifically, it is rare to see deformed rhododendron leaves with a gray powder on them. Some notable exceptions include many azaleas as well as 'Purple Splendor' and 'Vulcans Flame'.

mildew symptoms...

Powdery mildew symptoms in rhododendrons appear first on the leaves...with light green or yellow blotches on the upper surfaces and brown to purple spots or feathery areas on the lower surfaces. In severe cases, partial or complete defoliation and stem dieback can occur between late Summer and early Spring.

The Microsphaera fungi seem to be able to infect most rhododendrons, but some are more susceptible to powdery mildew than others. Some highly susceptible examples include, R. cinnabarinum, R. campylocarpum, 'Elizabeth', 'Virginia Richards', 'Unique', the 'Loderi' grex and many deciduous azaleas. Less susceptible plants are R. degronianum ssp. yakushimanum and its hybrids, rhododendrons with indumentum, and our local native species R. macrophyllum and R. albiflorum.

mildew flourishes...

Powdery mildew flourishes in locations with warm, sunny days, and cool humid nights. Especially favorable conditions occur in areas where plants are crowded and there is poor air circulation. Under such conditions, fungus spores can be produced within sixty hours of an initial infection...and then...ready to be spread around the garden by means of wind or rain.

Microsphaera spores prefer to germinate on dry leaf surfaces where they quickly infect the plant by sending specialized cells called "haustoria" into the leaf tissue to absorb nutrients. Young, soft rhododendron leaves are most easily attacked by powdery mildew although symptoms may not be evident until the leaves mature. Spores can over-winter on lower leave surfaces or in buds and will attack new leaves that develop the following Spring.

Prevention and treatment of powdery mildew can involve both cultural controls and chemical sprays.

chemical controls...

Fungicides will not remove the damage to infected leaves. However, if there are symptoms on last year's leaves, you might consider spraying the new Spring growth to protect against further infection. Trifloriine (Funginex) and sulphur sprays, such as Safer's Garden Fungicide are registered for use by homeowners. Newer, potassium bicarbonate baking soda) based sprays show some promise. In all cases, full leaf coverage with the spray is essential. Follow label instructions closely and wear protective goggles and clothing.

cultural controls...

Maintain healthy plants by providing good soil drainage and adequate water and nutrients. Stressed rhododendrons are more susceptible to disease. However, avoid over fertilizing, especially late in the season, as this practice encourages soft new growth that is a prime target for Microsphaera spores.

Inspect your rhododendrons regularly to identify infected plants and problematic areas on the garden.

Move infected plants to areas that have less favorable conditions for the disease. Be particularly careful to have plenty of space for R. cinnabarinum, R. thomsonii, and their hybrids. Try to plant them in areas with a fair amount of sunshine and good air circulation.

Prune to increase air circulation. At the University of British Columbia Botanical Garden, they do nothing to rhododendrons to control powdery mildew other than occasional thinning of both the surrounding material and the rhododendrons themselves.

Remove old, heavily infected leaves from rhododendron in Fall or Winter. Rake up diseased leaves that have fallen under the plant and burn them or dispose of them in the garbage.

If all else fails, discard heavily infected plants and replace them with rhodies that are more resistant to powdery mildew.

- Ron Knight, Vancouver Chapter

Dr. Rhody, another question...splindly growth...

Dr. Rhody,

I bought a lovely compact plant last Fall. It bloomed and was very lovely. Now new growth is coming out and it is very long and flimsy. What can I do to keep the plant from being spindly.

pinch...pinch...pinch

Dr. Rhody responses: When commercial growers force plants they fertilize and water frequently. This causes the plant to grow rapidly. At the nursery they frequently pinch...remove...the first new growth. Then the second spurt of growth is more dense and stronger.

The first year you own a plant it still has a large residual building up of fertilizer and the growth may be quite long. To maintain a more compact plant you can pinch the new growth during the Spring. One of the best growers I know actually says he pinches new growth up to July 1st. I wouldn't suggest you do that...but you are very safe to pinch growth early in the year and still look forward to nice blooms next year.

- Dr. Rhody

Todd's basic soil philosophy.

There's a man in the Vancouver Rhododendron Society who solves people's problems with their soil and plants and wisely shares it with others. It's Norm Todd and his philosophy on soils and soil preparation is so important. This issue of Rhododendron and Azalea News is a little late...but still early enough for all to review Norm's ideas and put them into use...come Spring...in a matter of weeks. Listen...

Healthy soil is a primary requirement of a healthy garden. Important components of a healthy soil are good water and nutrient-holding ability. These qualities are usually provided by the finer-textured components...such as clays and partially decomposed organic matter.

good aeration essential...

Good aeration is also essential to the various biological processes necessary for plant growth. Aeration in soil is provided by a variety of particle sizes throughout the profile, including larger materials…such as sands and gravels...and by natural soil aggregates...crumbs...which are made up of both mineral and organic soil constituents.

ways to build a healthy soil...

In general...the deeper the soil...the healthier the plants will be. Microorganisms, including fungi and bacteria, and macro-organisms...such as insects and earthworms, all contribute to building healthy, productive soil. Encourage them to live in the soil by maintaining good soil structure and avoiding the use of herbicides, soil sterilants or other chemical that kill or discourage beneficial organisms.

Finally, good drainage is essential in the Vancouver, Canada, Winter rainy climate. And, it may be true for you somewhere else around the globe.

examples of poor soil...

• Sand and gravel...do have the ability to retain water or nutrients.

• Clay...has very little air-filled porosity and retains excess moisture.

• Hardpan...because water and air will not penetrate it.

amending and preparing soil before planting...

• Break up layers or barriers in the soil that prevent free drainage.
• Ensure surface moisture can infiltrate the soil so it does not wash across the garden.
• Use prepared organic matter to improve the soil...well-rotted manure, compost from yard and kitchen waste, peat moss, seaweeds, composted bark mulch, and leaf mold.
• Fine sand will not improve drainage, but will fill in pore spaces.
• Work the soil during dry weather...working soil during rain will damage soil structure.
• Do not remove small sticks and rocks...they help build good soil structure.
• Do no break up soil crumbs...lumps of soil...fist size or smaller.
• Repeated use of a rotortiller often creates an impervious layer at blade depth. Operate at the lowest speed and gear.
• Test the soil before adding lime. Rhododendrons prefer a pH between 5 and 6.
• A little bone meal goes a long way...One tablespoon to the root zone of a 5-ft. tree.
• Do not add granular fertilizer to the soil when amending it. The granules begin to release on contact with the soil, and there are no roots there to benefit.
• Amend soil to a depth of 12-14 inches...even up to 24 inches...for annuals and perennials. For trees and shrubs, amend 24-36 inches...and if you can't go down, then build up above the existing grade.
• Do not leave the soil surface bare...always mulch to protect it.

Flower bulbs like electric light bulbs

The Nanaimo Rhododendron Society showed a cartoon in their February 2006 newsletter comparing flower bulbs with light bulbs. Pretty clever! Maybe sometime in the future, R&A News may be able to share drawings and illustration. For now...will share the comment:

Like flower bulbs,
electric light bulbs
can be planted in the ground.
They will grow into standard lamps
from which free bulbs can be harvested!

Pruning with Don Janssen

February is not thought of as a gardening month, but can include a few yard and garden activities. Outdoors...everything is weather permitting...but there are things to do inside in anticipation of Spring and the 2009 growing season.

Apples should be pruned on a regular basis to keep them productive...February through early April is a good time to do it.

be careful with other trees and shrubs...

Other trees and shrubs can be pruned...but be careful! Do not prune Spring blooming shrubs...such as forsythia, rhododendron, or lilac...because flower buds were formed last season. Cut them off and the shrubs will not produce flowers in the Spring.

Likewise, avoid pruning maples and elms until early summer.

other activities to do now...

Another good outdoor activity...beginning now...is to scout around the yard, looking for problems that may be corrected by pruning. For example: look for branches that are broken, crossing each other, too low, or growing into buildings or other undesirable areas. As weather conditions get warmer, these limbs can be removed.

draw plan for vegetable garden...

If you have not already started, now is the time for planning your 2009 vegetable garden. Draw up a plan of the garden space and allocate appropriate space for all the vegetables you plan to grow. When ordering specific vegetables, look for disease resistant varieties. These selections may produce a crop even if conditions are favorable for destructive diseases.

Now is also a good time for preparing to grow vegetable and flower transplants indoors. Basics include a good growing medium, adequate lighting and warm temperature. An advantage of growing your own transplants may be a wider selection of cultivars than purchasing transplants later this Spring.

However, growing your own requires suitable conditions and space, proper timing to assure transplants are ready for outdoors at the right time, and regular maintenance. After weighing all these factors, purchasing transplants later this Spring may be wiser for many gardeners.

Note: Don Janssen is an extension educator for Lancaster County, University of Nebraska. The comments shown above were gleaned from the Nanaimo Rhododendron Society's February 2006 newsletter.

Something to think about...

When everything seems to be going against you,
Remember that the airplane takes off against the wind,
Not with it.

- Henry Ford