Spring’s coming, so make sure trees get nutrients

Can you believe spring is about to burst? Fruit buds are swelling, and in a fortnight or so almonds and apricots will be in full bloom.

This time of year places a great demand on fruit trees for nutrients. New twigs are elongating, leaves unfolding, flowers opening and fruit setting on. It's as busy as the Strip on New Year's Eve inside those trees. Are your trees ready for this explosion?

It takes time to convert fertilizer to a form plants can use, and make the trip through the plant and finally to the fruit buds. This means you need to feed your trees soon.

Fruit trees require all the basic nutrients. We need to focus on nitrogen, phosphorous, potassium and iron, because our soils furnish the others.

Nitrogen is the key factor in making new shoots and keeping plants vigorously growing to produce a bountiful crop, but it's mobile. With our continued irrigations, it leeches away so we must replenish it more often.

Phosphorus, potassium and iron are more stable and needed in smaller amounts.

Here's how to tell if your tree needs nitrogen. Observe last year's shoots; they need to be at least 10 to 12 inches long. Anything less means adding more nitrogen. If the twig growth is longer, add less.

Your nursery sells a balanced fruit tree fertilizer, so follow its directions for the amount to apply. Place the fertilizer at the drip line or outer edges of the branches where the feeder roots are found. If your tree is in your lawn, fertilize the area under the tree twice.

Newly planted trees do not require much nitrogen the first year, but because of our long season we need to add some. Dissolve a tablespoon of fertilizer in a gallon of water and drench the area under the tree monthly until August.

Follow all applications with a deep irrigation to move the nutrients to the rooted area.

Don't neglect your shade trees and shrubs. They also need the boost. Mature shade trees require three times more nitrogen than fruit trees. If your shade trees are in your lawn area, apply the fertilizer using the same method as for fruit trees.

Pruning fruit trees: Winter is the best time to prune fruit trees because it's easier to see what needs to be pruned out without the leaves on the tree. Prune before the trees blossom to stimulate quality fruit production.

It's almost impossible to describe pruning; it's more of a visual process. Each tree has its own characteristics, making it difficult to generalize. Also, there are multiple approaches, most of which are valid and depend on individual preferences.

You need hand pruners, loppers, a pruning saw and a pair of gloves, especially if your tools are sharp.

There are a few general strategies used in pruning fruit trees. First, know where the fruit grows on your trees. Peaches and nectarines produce on last year's new wood. Apples and pears produce fruit on spurs - they look like spurs on a rooster's legs - along older branches, which produces fruit for several years. Plums and apricots produce fruit on both older and newer spurs along branches. With this information in mind, remove about half of last year's twigs on peaches and nectarines.

If you prune right, over the years, you'll never remove large branches. If you must remove a large branch, make the cut just beyond the branch collar (swollen area wrapped around the branch where it attaches to trunk). Within that collar are hormones to quicken healing.

Get rid of all dead, diseased wood, crisscrossing branches and shoots growing straight up. They'll be fruitless and rob nutrients the trees need to produce the desired fruit. Clip them off while they are still small. And thin out side shoots by removing every other one to help control the tree's size.

To maintain the tree's size in a small garden, also prune it during July and August. The response to the summer pruning is slower and directs the tree's energy to increasing larger and more colorful fruit. Avoid removing too much to prevent sunburn of the limbs. If you expose larger limbs, whitewash or paint them with a water-based latex paint.

Finally, spray dormant oil over the tree to kill any overwintering insects. The best time to apply this oil is just before the fruit buds open, that is, when the insects are easiest to kill.

Linn Mills' garden column appears on Sundays. You can reach him at linnmillslv@gmail.com or call him
at 526-1495.