Archive for January, 2015

Apples in September

Mature apple tree in full bloom.

Mature apple tree in full bloom.

After working hard to plant and nurture your fruit trees, it can be very discouraging if you are not soon rewarded with a bountiful crop of delicious fruit.

Since many fruit trees can take up to 5-6 years (or more) before they are old enough to bear, problems with fruiting may not become evident right away – which is even more frustrating.

There are several reasons why fruit trees fail to bear; but one of the most common is lack of pollination. If the flowers are not pollinated, fruit cannot develop (in most cases).

What leads to pollination problems?

Japanese plum blooms in spring.

Japanese plum blooms in spring.

Many fruit trees, for example apples, pears, sweet cherries, and many plums, require cross-pollination in order to set fruit.

If you are growing these types of fruit trees, you must have at least two compatible varieties planted within 50 feet of each other in order to ensure successful pollination. Compatible varieties are those that are in bloom at the same time and have compatible pollen.

For instance if you want to grow Gala apples, you will need to plant at least one other variety, such as Braeburn, Fuji, or Granny Smith, as a pollenizer. These are just a few of the many apple varieties that would successfully cross-pollinate Gala.

Crabapples produce pollen that is compatible with many apple tree varieties.

Crabapple pollen is compatible with
many apple tree varieties.

In fact, most apple varieties have quite a number of different trees that can act as a “pollination partner” – you just need to do a bit of research. Even crabapples will meet the pollination requirements of many apple trees.

Almost all varieties of pears require cross-pollination. Even more specifically, Asian pears require another compatible Asian pear for pollination and European pears require another European pear as a pollination partner. These two pear types cannot cross-pollinate each other.

This is also true of Japanese and European plums.

How do you find a compatible variety? Sometimes the pot tag will recommend a pollenizer or the nursery staff where you purchase the tree can suggest compatible trees. If you purchase from a mail order company, their catalog or website will suggest the best pollination partners for a particular variety. This holds true for all fruit trees that require cross-pollination.

Most peach trees are self-pollinating.

Most peach varieties are

Some fruit trees are self-pollinating or self-fruitful, meaning they can set fruit without cross-pollination with another variety. These include most varieties of peaches, apricots, nectarines, and sour cherries. In the case of self-pollinating fruit trees, only one tree has to be planted in order to get fruit.

However, most of these trees will bear more reliably or produce heavier crops if more than one variety is planted. Cross pollination will usually improve fruit set.

This may explain why we have never gotten apricots on our solitary apricot tree even though it is hardy in our area and is supposed to be self-pollinating. It blooms beautifully but only a few fruits form and these always drop off when they are quite small – sounds like a pollination issue to me.

Of course there are other reasons why fruit trees may fail to produce fruit.

Environmental conditions can affect fruit set in some years.

  • A honey bee visits a crabapple flower

    A honey bee visits a
    crabapple flower

    A very cold winter can damage or kill the dormant flower buds. This is especially common when fruit trees are planted on the fringe of their hardiness range. Obviously, this will result in few or no flowers the following spring.

  • Late spring freezes or frosts just before or during the bloom period can damage or kill the flowers before pollination occurs.
  • Misty, rainy, or cold weather at the time of flowering can inhibit or limit pollination because bees are not as active in these conditions. If weather like this persists, it can affect pollination and result in a reduced fruit crop.

Poor pruning practices; avoid over-pruning or pruning at the wrong time

Poor nutrition due to lack of fertilizing. Espoma Tree-tone is a good organic fertilizer for all fruit trees. Apply in the early spring before growth begins and in the fall after the leaves drop but before the ground freezes.

In severe cases, cedar-apple rust can weaken and eventually kill apple trees.

In severe cases, cedar-apple rust can
weaken and eventually kill apple trees.

Disease or insect damage to flowers or flower parts can prevent successful pollination. Spray in late winter with a horticultural oil such as Bonide All Seasons Oil and follow a recommended spray schedule through the growing season.

Trees are weak due to repeated disease problems, insect infestations, or poor care.

The bottom line

Before you purchase your fruit trees, be sure to do your research!

  • Choose varieties that are hardy in your area.
  • If cross-pollination is required, choose two or three varieties that are compatible and will successfully cross pollinate each other.
  • Remember that even self-pollinating varieties will benefit from cross-pollination.
  • Keep your trees properly fertilized and watered.
  • Prune your trees according to the training system recommended for each particular fruit type.

Let’s grow some fruit!

Until next time – Happy Gardening!

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Rime ice settled on winterberry fruit

Freezing fog was lifting

The fog was lifting by 9:00am

It was beautiful yesterday morning. The sun was beginning to come up through a hazy fog as I looked out of the window. I could just see a hint of orange glow through the trees. It was 21°F and there was still a dusting of snow on the ground from our little snow squall the day before.

Looking off to the west, the fog seemed a bit denser and the trees looked ghostly white in the distance.

The fog was lifting by the time I was driving to work but the crystalline world that it left behind was breathtaking. The trees, shrubs, fences, and almost any solid surface were covered with white ice crystals.

Rime ice covers the tree branches

Rime ice covers the tree branches

My first thought was that this was hoar frost but hoar frost develops on cold, clear nights. Wednesday night had been cold but overcast. As dawn approached, the humidity rose above 90% and the dew point dropped to within 2 degrees of the air temperature (data from Weather Underground). The combination of these two things led to the formation of a light fog.

Because the temperature was so cold, the tiny droplets of water that made up the fog became “supercooled” but remained liquid – until they came in contact with a solid surface at which point they froze almost immediately, forming beautiful ice crystals on whatever they touched.

Rime ice covers dogwood branches

Rime ice covers branches of a dogwood

This phenomenon is called freezing fog and the ice crystals that it forms are called rime ice. Hoar frost can look very similar to rime ice but hoar frost forms when the water vapor in the air turns directly to ice crystals without first condensing into water droplets. This can occur on cold, clear nights. Rime ice forms from fog (freezing fog).

The tops of mountains are often covered with rime in the winter. I often see it in Vermont when low clouds envelop the mountains (fog is just a type of low-lying cloud). When the clouds lift, the trees on the mountain tops are cloaked in brilliant white ice crystals. It is beautiful!

Rime ice covers trees on top of Bromley Mountain in Vermont

A heavy coating of rime ice covers trees on Bromley Mountain in Vermont

I wandered around the nursery gardens for a while armed with just my iPhone for a camera. When I left the house, I didn’t expect to find myself in the midst of a spectacular winter wonderland! Oh well, I still managed to capture some of the beautiful ice formations before the sun managed to destroy them.

Until next time – Happy Gardening!

Rime ice covers pine needles

Beautiful mahonia foliage is outlined by crystals of rime ice.

Beautiful mahonia foliage is outlined by crystals of rime ice.

Flower buds of Mahonia are covered with ice crystals

Flower buds of Mahonia are covered with ice crystals

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sapsucker damage to white birch

Woodpeckers are a common sight around our house. We often hear their cackling calls as they fly through the woods or the drumming of their beaks on dead trees as they search for insects.

A male downy woodpecker

A male downy woodpecker

Red-bellied woodpeckers are frequent visitors to our suet feeders as are the little downy woodpeckers. Less common at the feeders are hairy woodpeckers, pileated woodpeckers, flickers, and yellow-bellied sapsuckers. The flickers and sapsuckers normally just come for the water we always provide on our deck.

Pileated woodpeckers are really awesome birds. They are the largest woodpeckers in the U.S. (assuming the larger ivory-billed woodpecker is truly extinct). Once in a while, one will fly in to the suet feeder but we normally just see them flying through the woods. These large woodpeckers have a crazy, undulating flight pattern which catches your eye if you happen to be looking in their direction.

Pileated woodpeckers are striking birds

Pileated woodpeckers are striking birds

We usually hear them more often than see them, though. They have a very loud and distinctive “wuk, wuk, wuk” call as they fly through the woods. Almost like something you’d hear in a tropical jungle. Very cool to hear!

Pileated woodpeckers also make their presence known by the loud hammering sound they make as they drill powerfully into dead trees in search of their favorite food, carpenter ants. I’m happy for them to eat all the carpenter ants they can find!

They create a very characteristic rectangular hole as they peck, shred, and tear away at the rotten wood, usually leaving a pile of wood chips at the base of the tree. Most other woodpecker species excavate holes that are round rather than oblong.

Rectangular holes drilled in a dead tree by a pileated woodpecker

Rectangular holes drilled in a dead
tree by a pileated woodpecker

Wood chips pile up at the base of the tree

Wood chips pile up under the tree

Last fall, we watched a male pileated woodpecker chip away at the base of a large dead pine in our yard. We had had the tree cut down years ago but asked the tree company to leave about a 20-foot stump – just for the woodpeckers. I guess the woodpeckers, insects, and the weather finally took a toll on the stump because a few weeks ago, it just fell over and rolled down the hill!

Most woodpeckers do not damage live trees. They normally feed on trees that are already dead or those that are so heavily infested with insects that they soon will be. Like the nuthatches and brown creepers, they sometimes feed on insects living in the bark crevices of live trees but this usually doesn’t harm the tree. Nest cavities are generally excavated in dead trees. If you want to encourage woodpeckers, leave some dead trees standing in your woods – as long as they are not a threat to anything or anyone when they eventually fall.

Male yellow-bellied sapsucker

Male yellow-bellied sapsucker

One group of woodpeckers, the sapsuckers, is an exception. These destructive woodpeckers drill a series of small holes in the bark of live trees and feed on the sap that pools and flows from the holes. They have a specialized tongue for lapping up the sap. Sapsuckers also feed on small insects that are attracted to the sweet sap but unlike most other woodpeckers, their main food source is tree sap.

The yellow-bellied sapsucker is common in our area. It is similar in coloration to the downy and hairy woodpeckers but is between these two in size. Both the male and female have a bright red crown on top of their head which distinguishes them from these other two species.

Male hairy woodpecker - black crown, white breast

Male hairy woodpecker –
black crown, white breast

Male downy and hairy woodpeckers have a black crown and a red patch on the back of their head not on the top and the females have no red markings at all. Male yellow-bellied sapsuckers also have a bright red throat. I’m just telling you this so you won’t blame these other woodpeckers for the destruction caused by sapsuckers!

Sapsucker holes are drilled very close together in horizontal or vertical rows. The pattern is very distinctive. They can kill a tree outright if they drill enough holes to girdle it. At the very least the holes are unsightly and can also provide a pathway for disease and insects to enter the tree.

Though yellow-bellied sapsuckers feed on many different tree species, they are partial to birch and maple trees because of the high sugar content of their sap. There are quite a few white birch trees on my mom’s property in Vermont that have sapsucker damage and my sister has problems with them damaging the birch trees she has planted in her landscape.

Sapsucker holes in this white birch probably led to its death.

Sapsucker holes in this white
birch probably led to its death.

Sapsucker damage; viburnum

Sapsucker damage; viburnum

There are a few things you can do to try and stop sapsuckers from drilling into your trees. One method is to wrap burlap around the trunks where they are actively drilling holes. My sister has done this and it has helped to some extent. Hanging visual repellents like flashy CD’s, pie tins, or hawk silhouettes from branches of the tree being damaged has also been known to work.

These birds are protected by the Migratory Bird Treaty Act so lethal control methods are not an option.

All-in-all, woodpeckers (except the sapsuckers!) are pretty nice to have around because they eat many of the insects that are destructive to our trees. They dig out borers, beetle larvae, carpenter ants, and feast on many of the foliage eating caterpillars. I would say they are “friends”!

Until next time – Happy Gardening!

Extensive sapsucker drilling has girdled and killed this pecan tree. Photo sent by Shelby. See comments below ...

Extensive sapsucker drilling has girdled and killed this pecan tree. Photo sent by Shelby. See comments below …

A female yellow bellied sapsucker is caught in the act on Shelby's pecan tree.

A female yellow bellied sapsucker is caught in the act
on Shelby’s pecan tree.

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