You Ask…the Experts Answer!

Q. Everything on our patio (furniture, plants, brick, etc.) is covered with tiny dots of sticky stuff. We're assuming it's coming from our trees? What is it and how can we get rid of it?

 A. You've described "honeydew," the sugar-laced water excreted by aphids as they suck up sugar-laden sap flowing through the leaves of your trees.

 The good news is that despite the mess, the aphids cause little damage to your trees. Therefore, I find it very difficult to recommend the application of insecticides to manage what I consider to be a nuisance infestation. And, even if you were to apply insecticides - which would require commercial equipment to effectively reach high into large trees—it's quite possible the application would be only marginally effective at reducing the nuisance you're experiencing. Sometimes a pesticide application make matters worse because beneficial insects are killed with insecticides and then in time pest population jumps unchecked.

 Another bit of good news is that these mid-summer nuisance infestations give us an opportunity to watch nature in action as along with increasing aphid populations, lady beetles are never far behind. 

The beetles lay clusters of creamy yellow to orange eggs on the undersides of leaves in close proximity to feeding aphids. Within a matter of days, the eggs hatch and swarms of fierce-looking, black and orange alligator-shaped lady beetle larvae quickly swarm out onto infested leaves. Before pupating into an adult beetle, each larva may eat hundreds of aphids!

 Ultimately, the voracious appetite of lady beetles is often enough to bring high populations of aphids down to levels similar to what might be expected with the application of an insecticide - the process just takes a little longer! 

Shortly after hatching, tiny, alligator-shaped lady beetle larvae can crawl forty feet or more in search of aphids, their favorite food. 

This issue’s guest expert is Liz Berkeley, Horticulture Lab Diagnostician at Monroe County Cornell Cooperative Extension.

Q. What is soil testing and why do I need it?

A. A soil test, or what we commonly refer at Cornell Cooperative Extension as a soil nutrient analysis, provides information on the amount of nutrients that are found in the soil. It also provides the soil pH, which is a measure of how acid or alkaline the soil is. Any pH value below 7.0 is considered acidic and above 7.0 is alkaline, although there are varying degrees of acidity and alkalinity.

Some plants grow well over a wide range of soil pH, while others grow best within a narrow range. Most turfgrasses, flowers, and ornamental shrubs grow well in a pH of 6.0 – 8.0.  Vegetables, and fruits grow best in slightly acid soils. Plants such as rhododendron, azalea, andromeda, mountain laurel, and blueberries require a more acidic soil to grow well.

There are several nutrients that are essential for plant growth. Many of the most important nutrients are available between 6.5 and 7.5. When pH rises above this value, nutrients such as phosphorus, iron, manganese, copper, and zinc become less available. Pin oak and red maple are two trees that exhibit poor leaf color and growth when the pH is too high.

For the most part, while there are pockets of acidic soils, Buffalo, Rochester and Syracuse are situated on lime bedrock. This results in most soils being alkaline. Much of the rest of the state has acidic soils. A soil test is the only precise way to determine whether the soil is acidic, neutral, or alkaline and to offer recommendations for how much lime (which raises the pH) or how much sulfur (which lowers the pH) is needed to adjust the pH.

All of this is helpful information in determining the proper amount of fertilizer to apply for good plant growth without applying too much, thereby protecting the environment.

Q: When is the proper time to tap a sugar maple?  

A: Tapping usually begins late February or early March when we have below-freezing nights and above-freezing days. This change in temperature causes pressure within the tree that causes the sap to flow out of any drilled or natural wound.  You may notice trees dripping from broken branches at this time of year—broken by Mother Nature’s natural pruning shears, the wind.  Other natural clues include the constant calling of crows, the drip of melting icicles and the “see you” love song of the chickadee. 

 Q: Why the sugar maple?

 A: Although all trees have sap that could be boiled down into syrup, the sugar maple has the highest sugar content and therefore takes less labor to make the syrup or sugar.  I personally have tasted syrup from birch and pine and find it quite strong and bitter, but it’s all a matter of personal taste!

Q: My Benjamin ficus is looking forlorn. Any advice?

Ficus benjamina is a lovely graceful plant that can lend a touch of elegance to any room.  And I believe that deep in its chorophylled soul it knows it.  It is a primadona in the parlor.  Move it and it will defy you by dropping its leaves.  You can almost hear it muttering, “Don’t touch me.”  It likes bright light and a lot of humidity, but not much water. It prefers being slightly dry between watering, but not too dry or it will morph its pretty green leaves into an ugly yellow mess. I basically just leave my ficus alone.  I have placed it in an artistic pot and it seems to appreciate this gesture.  Every once in a while I very very gently dust its leaves with a baby-soft cloth dipped in tepid water.

If you would like a plant that will love you and not test you, I will recommend two.  First there is the sansevieria, also known as mother-in-law’s tongue, which will happily lend a vertical architectural presence to a lower-light corner of your home.  And second is aloe, which likes more light. This one is worth having around for the burn-relieving properties of its juices.

 Q: How do I force branches to flower indoors?

 A: This is a great way to not only ease the bleak days of winter, but also to prune your shrubs and trees. At this time of year it is easy to see branches that are rubbing, weak, or not contributing to the preferred shape of the plant.

 You can begin the process when the temperature has been below 40 for about 6- 8 weeks, usually sometime after the first of January, depending on your locale.  It is best to begin on a sunny day when the temperature is above freezing.  Your spirits will be rising and the sap will be flowing.  Look for nice plump buds which will eventually evolve into flowers. (The smaller buds will become the leaves.)  With a clean, sharp pair of pruning shears make your cut flush with a major branch.  Remember that you will be removing some of the spring display so try to cut from the more crowded areas of the plant.

When you come inside make a diagonal cut right above the first one.  If you are dealing with a woody stem gently mash it with a hammer or the back of your shears and then submerge all the branches in cool water for a couple of hours.  After this initial immersion place them upright in a container with three to four inches of warm water, first removing the lower buds and twigs.  If you have some plant preservative add it now to help cut down on bacterial activity.  Place the container in a cooler location. Change the water daily but keep it at the same low level.

When the buds begin to swell and show some color (and they really will!) bring the container into a warm room.  The blooms that you’ve been waiting for will arrive and reward your diligence.  If you keep them out of direct sun, the floral display will last longer.

This procedure works well with both shrubs and trees.  Forsythia and pussy willows will blossom quickly.  Tree branches will take longer.

Q: I’ve heard something about using the words “madcap horse” when identifying trees. Can you explain what this is?

—Confused, Mumford

A. The "madcap horse" is a mnemonic (memory aid) for distinguishing which North American tree and shrub species have an opposite branching pattern, as opposed to an alternate pattern. Most native trees have an alternate pattern, which means new buds and branches form in a staggered fashion along the stem or branch. A fewer number of trees branch in an opposite manner, meaning the buds form in pairs directly opposite one another. The letters and word fragments in "madcap horse" each refer to a group of plants with /opposite/ branching, as follows:

M = maple

A = ash
D = dogwood
CAP = Caprifoliaceae (the viburnum family)
HORSE = horse chestnut (Aesculus hippocastanum, also known as buckeye and Spanish chestnut) 

If, when looking at the branching pattern of an unknown native tree or shrub, you determine that the pattern is opposite, you know that it belongs to one of the above groupings. You can then use additional characteristics (leaf shape, flower, fruit, bark, etc.) to narrow your choices further. If, however, the pattern is alternate, all you will know is that it does NOT belong to one of these groups, and that you need to find another method of identification, such as a dichotomous key or a good field guide. 

(Note that this mnemonic works only for trees and shrubs native to North America. There are many species from other parts of the world that have opposite arrangement of branches, several of which can now be found as ornamental plantings in the United States.)

---

—J. M., via e-mail 

A: I’ve spent years of struggling with the problems you mention. Plants used in such situations must fit into these categories: interesting shape and structure, berries or good seed heads and durable evergreens. Focus on plants that like heavy soil—if they have happy feet, they can probably endure the wind and sun. Forget the list of things deer won’t eat. My experience has shown me that they will eat anything if they are hungry enough. For that reason I try to stick to deciduous material that will bounce back quickly if nibbled.
 
Here are some choices that have worked for me. Let’s start with trees. You have to rely on structural interest in the winter.  One of my favorites is weeping crabapple (Malus x ‘Red Jade’).  Its vertical flowing branches add a nice dimension to the garden and it produces berries heavily in the fall—the birds love it.  Curly willow (Salix matsudana tortuosa) also tolerates heavy soil and its twisting habit is fun to look at poking through the snow. If interesting bark appeals to you the paperbark maple (Acer griseum) can’t be beat for its papery, cinnamon-colored bark.
 
With deciduous shrubs, you don’t have to contend with winter burn. I’m fond of those that have colorful bark. Some of the dogwoods such as red twig (Cornus alba sibirica) or yellow twig (Cornus ‘Bud’s Yellow’) make a vibrant contrast against a snowy landscape. Shrubs with berries are a plus too, such as Ilex verticillata, is a good choice for heavy soil. There aren’t many evergreens that can endure this type of site. Some of the blue spruces (Picea spp.) are stunning in the winter garden. Picea pungens ‘Montgomery Blue’ is a nice one that doesn’t get too large (4-5 ft). Some get fairly tall (30-40ft) so make sure the variety you pick will fit your site. Ilex crenata is by far the best dark green shrub I’ve tried. The berries are unexciting but it’s a tough shrub and repairs itself quickly in the spring.

Don’t overlook perennials for winter interest. Ornamental grasses such as miscanthus, calamagrostis and panicum produce seed heads that attract birds and are interesting to look at most of the winter. A few that pair up nicely with grasses are Joe Pye weed (Eupatorium maculatum), Rudbeckia maxima, Echinops‘Veitch’s Blue’ and Sedum ‘Autumn Joy’.