April in the Orchard
This article is a reprinted exerpt from April, 2013 written by Dr. Bob Norton, one of the VIFC founders.
I’ve just come in from the pouring rain, having fertilized the weaker apple, peach and plum trees. I goofed not getting out a March Newsletter-too many things going on both in and out of the orchard. In March, the dormant pruning and then the grafting were finished, trees planted in the Club’s nursery at Bruce Jackson’s. Now it’s mid-April. Here’s how it looks and what we might look for and perhaps take care of.
What does your potential fruit crop look like? Judging from the fruit buds on my trees, I’m looking at a very heavy crop on almost all of the trees-apples, pears, cherries and even apricots. The dwarf apples on M9, B9 and M27 have excessive flower buds, meaning they need careful thinning, starting now! Hard to do, but it’s a good idea to thin out some of the cluster buds before they open. This will tend to offset biennial bearing, meaning that the spurs you remove the flower buds from will be more likely to become flowering spurs next year, while this year’s fruiting spurs may rest next year, causing biennial bearing. Delaying the thinning until you have a gillion little apples set won’t have much effect on fruit bud set for next year.
Why fertilize now? Most of my trees-apples, cherries and pears-are on dwarfing rootstocks (B9, M9, M27, Quince and Gisela5) with shallow root systems, likely to “runt” out, producing poor new growth and small fruit if not properly fertilized and watered. Therefore, I need to observe the annual new growth and if necessary fertilize to stimulate at least 8-10 inches of new growth annually. This is the best time of the year to do this because we will get enough rain to take the fertilizer into the soil before the dry season. If applied in the fall or winter most of the nitrogen would be leached out. If your trees are freestanding semi-dwarf or full size, the need for fertilization is less important. You may be more interested in slowing your trees down. That’s where summer pruning, letting the grass grow and holding back on water becomes more important.
The upcoming meeting on April 24 will go into detail on pollination, specifically the pollinators-honeybees, mason bees and other insects. By this date, apples and pears should be in bloom, cherries, peaches and Japanese pears at petal fall stage and strawberries in various stages of bloom depending on variety. At this time we might watch for leaf rollers on apples (easily squished), aphids on plums and sometime apples (maybe ignored), but if you are growing stone fruits you can’t ignore brown rot (Monilinia). As the daily temperature rises above 60 degrees and the humidity remains high, this disease can wipe out your crop of cherries, apricots, peaches or even plums. Fungicide application can reduce infection but keeping the trees open so that the fruits dry off quickly after a rain is equally important. My 8x8 foot spacing puts the trees closer than perhaps they should be, so I have to be very careful to remove infected flowers and twigs and spray fungicides during wet periods. Is it too late to prune? Heavens no! My peaches and apricots will get their main pruning later this month or in May when I can see what kind of a crop is set. If the crop is heavy, fruit thinning and some branch thinning will be done to adjust the crop so that the remaining fruit will obtain good size. With peaches, I’ll remove doubles (two fruitlets stuck together). Plums may over set (a rare situation) and thinning and pruning may be necessary to open the tree and balance the crop.
The rule of thumb is that the later you prune, the more stunting the effect on the tree. Makes sense doesn’t it? Removing leaves that produce the food (photosynthate) the tree needs to grow is bound to reduce vigor. If last year’s growth is weak, don’t prune heavily in spring or summer. This is what we mean by “reading the tree”. I walk through my orchard at least twice a week, observing new growth, tucking, pinching, maybe tying a branch up or down, removing flowers on branch tips, looking for insect or disease symptoms. This may not be your thing- you just want the fruit with a minimum of effort. Fine. You may find, however, that getting to know your trees becomes more fun and the trees will show their appreciation at harvest time.
Bob