I am curious to hear thoughts on the form of this Canadian White Blenheim. I planted it as a bareroot tree in spring 2020 and selected 3 primary scaffolds for open center shape. It has grown to current size roughly by fall 2021 and I allowed each scaffold to Y, ending up with 6 scaffolds in the upper canopy. Overall I am pretty happy with the form - but I was disappointed by the very small number of fruit buds this spring. Despite lot of small laterals on each scaffold, only the 1 year old growth at the tip of each scaffold (that which grew after summer heading cuts) developed flowers.
So what I’d like to accomplish is more fruit bud development, of course. To me there appears to be plenty of sunlight penetration into the tree, but I am second guessing the 6 upper canopy scaffolds - wondering if I should eliminate the Ys and prune down to 3 primary scaffolds. After reading old pruning article posted by @alan (which maybe was primarily focused on apples and pears) I am thinking that this being a vigorous variety - it may do better with a smaller number of scaffolds - though maybe I didn’t grasp it.
Any thoughts on direction to help this CWB make more fruit buds? Am I just being impatient and it just needs more time?
@scottfsmith - I have seen mention that CWB has been vigorously vegetative but not all that productive. Is this still your experience after replanting CWB?
Apricots require little thought to developing flowers and it isn’t your pruning that is delaying fruit production, in fact production isn’t truly delayed at all. peaches can usually give me some fruit the 2nd year if I grow them for max vigor but give your apricot another year or two- they take longer. Then you can figure out if that was the right cot to grow in your climate- I know nothing of it but do know that the Canadian breeding program has produced a lot of fine varieties- I think the best one is Hargrand here in southern NY. However, in Idaho you may need two varieties to get consistent bearing, as we do here, unlike same varieties in CA- not that that is your problem yet, since you aren’t getting much bloom to begin with.
Thanks Alan, that gives me some peace of mind. Impatience is often the cause of issues I have, haha. It seems that folks in dry climates like Nevada and Eastern WA are doing well with white apricots, but I will have to wait to see. I have another that I multi-grafted this year to try 4 other varieties - hopefully at least one of them will do well here in Boise.
Your tree has very long whips, which is natural habit of apricot trees. In the second/third week of August, head these whips to 50-40% of their length; this will stimulate growth of new short branches that are full of fruit buds, and will also help strengthen these whips to achieve a stronger tree structure.
I have never heard of your advice, nor have I ever had difficulty getting apricots to flower, so I don’t see how I could test it, but I am interested in the source of your method- what it’s based on. I fear it could very well make the trees more susceptible to winter kill as late hard pruning of peaches seems to. Apricots tend to be rather fragile in my climate which is much different than any place in Idaho, but Idaho certainly gets hard frosts at the wrong time occasionally.
As far as how I prune my cots, I do stick to my ratio approach unless I have 3 equal sized scaffolds that violate the rule and are all bigger than half the diameter of the trunk. I don’t like scaffolds to break into equal sized secondaries either because once the tree gets any size you have more highways than you need to hold the smaller wood that supports most of the fruit. Also, such branches are prone to breakage where they meet, although that may not be a problem with cots.
All white apricots with the possible exception of Sugar Pearls are not productive. At least that is my experience in my Maryland climate. I’m probably going to give up on them but will see if they might mature into being more productive. I was about to chop down my pomegranates but they finally decided to get going and produce a bit, so they are still standing (for now).
I haven’t had a lot of experience with Sugar Pearls, although I planted one in front of my house 3 years ago. It had a few fruit last year and more this one but at another site I manage I’ve seen a tree I planted of this variety loaded with fruit, but one season does not an evaluation make.
I think the fruit is especially delicious and sweet but Adams has stopped selling it so it may have some problems.
Is CWB related to regular Blenheim? I have 3 regular Blenheim that are borderline freeloaders. Half of one of them was converted to CWB this year and already has 3 foot. Don’t tell me I invited another freeloader home. There is a lot of other people claiming it is doing well for them.
I have to thin CWB each year, taking off maybe half to two-thirds of the fruit. Sugar Pearls requires a ton of thinning. Lots more work than CWB. Here’s some pics of thinning progress on CWB as of today.
I would definitely call that productive! @SpokanePeach do you have any zoomed out photos of your CWB? It would be cool to see the growth habit for me to get an idea of what a more mature tree form might look like.
The overcrowded highway is another reason I was thinking to eliminate the Ys, or equal sized secondaries, and go from 6 to 3 primary scaffolds. As I try to visualize the tree getting larger, I am imagining that the laterals may start crossing too much.
It is generally advised to prune apricots in the summer, when the weather is dry and trees are actively growing, as winter pruning expose them to bacterial canker infections. So, I have been pruning my cots twice, once in July right after harvest, and another around mid August since cots are vigorous growers and one summer pruning was not enough in my experience. I have been seeing the formation of fruit bud-rich wood (few inch long growth, covered by fruit buds) following the Aug pruning. In Wilmington, DE where I used to live, the first frost was typically mid to late Oct, and I never saw winter die back on my cots except for perhaps a couple of inches at the top of a few branches, nothing to worry about at all.
The stimulation of fruit bud formation by summer or late summer pruning is known for other fruit varieties, but I am not an expert to tell if it is a general behavior with most fruit types or not. Perhaps you can’t test it, but the original poster can, at least on a few branches if he is worried about doing it on all branches.
Peaches often are pruned during first growth commercially- at least Cornell recommends it- to reduce canker pressure. Cherries are often pruned post harvest to avoid canker. What I cannot find is any recommendations at all for apricots, but in my 30 years of growing them in the northeast I can’t say canker has been a big problem- not even on cherries much and not on peaches or cots at all. This is based on almost always doing structural pruning during dormancy- late dormancy for stone fruit.
The one thing I learned from commercial growers I’ve talked to over the years- the first priority is to have the time to prune and when you prune to your own convenience you can learn the real-world consequences of pruning at the “wrong” time.
The single thing about timing I have learned is not to prune young peach trees preceding single digit cold… That’s about it for timing pruning of stone fruit.
If you have any academic sources on proper timing of pruning cots, I’d be interested to see them, if only because I couldn’t find any for east coast growers. They just aren’t important enough commercially, apparently.
My teachers at the UC Santa Cruz Farm and Garden made no distinction to avoid winter pruning on stone fruits when growth stimulus was the desired effect, and I have pruned plenty of stone fruits in March/April with no major problems. However, I did notice over the past few years that I would get about 1/4 inch of dieback below my cut instead of clean healing - often drying out/killing the bud I had intentionally chose to grow. This year I switched to pruning my stone fruits in spring after petal fall, and have been pleased with much better wound healing. Personally, I don’t think the summer pruning only maxim for stone fruits is warranted if the desire is to stimulate vegetative growth/shape structure. But I am now a convert to late spring instead of dormant winter pruning.
To your point though, on this particular tree the best fruit bud development was on the growth extensions which followed by July pruning cuts so I think that is a good suggestion that you have made. In Boise, August pruning might be fine since it’s often warm into October. But I may stick to July since I have done that with no problems - but perhaps make stronger heading cuts as you have suggested.
I prune my own stonefruit trees including my nursery trees after they begin growing, incidentally. It is convenient for me to do it then, but I have a ton of pruning to do on orchards I manage and I’m doing it every working day from mid-Dec until about April. I will come back in mid-March to prune stone fruit in orchards I’ve pruned apples in the heart of winter and don’t usually prune stone fruit much before that.
I’m not as careful in pruning to specific buds as you- even on my own trees. It just doesn’t matter at this point- I have so many trees in production the idea is just to prune them open enough and to get it done. My hobby is also my full time job.
On a good year most of the orchards I manage produce way too much fruit for my customers.
@kunsangsean The second and third references above are from the university of California. Note that for California pruning in September is acceptable because they don’t get frosts in Oct/Nov like us.
July might be too early for such an effect, since the tree may still be in vigorous growth mode and produce normal/vegetative growth in response. Around mid Aug, growth would have somewhat slowed down, and the trees will probably respond differently. You can do half the branches in July and half in Aug to check the difference.
I lost a cherry and an apricot tree to canker, and I know others who did. Also, from the references that I shared above, it is clear that bacterial canker is a serious disease for cots, cherries and plums/prunes.
OK, I will give this a try. Please keep in mind that both of my trees are frankentrees with many varieties on each tree.
Pic below is both trees together. CWB base tree on the left, Sugar Pearls base tree on the right. The Sugar Pearls tree is 11 or 12 years old, the CWB is 4 years old if memory serves me correctly (this is the 3rd apricot in that location).
On this side of Sugar Pearls you can see a main branch of CWB with a silver tag hanging at the bottom. This was grafted several years ago and is a pretty good size now. There is another branch of CWB similar to this one on this tree as well.
Below is a pic of the younger CWB base tree. This one is pruned to an open center, but there are a lot of branches that need to be pruned off all of the various grafts on the tree which I will do after harvest in early August.
