I recently evaluated four Honeycrisp blocks in the Champlain Valley for their percentage of flowering buds so the growers could adjust their pruning practices. The blocks are described in the following table:

Below are this year’s results:

I considered strong floral buds those containing a full cluster of kings and laterals. I expect these buds will set fruit provided we have good spring weather and good pollination conditions. Weak floral buds were smaller, and often only had a single king in the cluster. I think these are going to be the smaller, single king flowers we often see on Honeycrisp, but are still likely to set fruit.  Vegetative buds only had leaf scales in the buds, no floral parts were present.

I shared these results with Dr. Robinson. His pruning suggestions were:

• The three blocks with >50% floral buds should be pruned normally, or by following the precision pruning program of leaving 1.8x the total number of target fruit per tree, and factoring in the percentage that are floral.  (Let’s use block 3 as an example.  Assume we want to end up with 100 apples per tree.   1.8 times 100 is 180.  Since only 68 percent our floral, we then divide 180 by 0.68 to arrive at 265 total buds should be left on each tree.
• Block 1 should be pruned more lightly, removing only one to two large limbs per tree.

These are of course just four blocks, and only serve as an example. Your Honeycrisp blocks are likely to vary in their percentages of floral buds this year, depending on:

·       your initial fruit bud load in 2024,

·       your thinning practices,

·       your return bloom practices,

·       along with other more difficult to define factors like tree stress during floral bud initiation.

If you are interested in evaluating buds in your own blocks, here are some of my thoughts from the experience:

·       I followed the protocol of two branches (one each from the upper and lower canopy) from 5 representative trees per block.

·        I looked at 10 spurs per branch, unless the branch had fewer than 10 spurs. If a spur had multiple buds, I chose a single bud from that spur at random. Since Honeycrisp spurs also have a tendency to produce bourse shoots, terminal buds on these were also fair game.

·        I used a single edged razor blade to cut through the middle of each bud length-wise (figure 1), and looked at the buds under a tabletop dissecting scope (figure 2). These can be purchased online for around $100. You’re also welcome to come in and use the one at the Clinton County CCE office.

·       In figure 3, you can see what a floral bud (top) vs. a vegetative bud (bottom) looks like under the scope. The vegetative buds are fairly narrow and will only have leaf primordia at the tip of the bud. Floral buds will appear more rounded, and will have small, light green floral tissues at the tip of the bud. These can be difficult to tell apart at first, so I recommend cutting open a few practice buds until you get your bearings on what is what. I find Honeycrisp particularly challenging to tell apart (it is Honeycrisp, after all). I also looked at buds with a hand lens but found I couldn’t distinguish the vegetative vs. the floral buds very readily with it.

·        After getting into the swing of things, each block was taking me about 70 minutes to fully assess. This does not include the time it took to cut the limbs from the orchard.

So, I recommend giving it a try if you have the time and interest. As stated above though, it can be very difficult to tell them apart, so you might want to prune lightly now, and then make more precise pruning adjustments after green tip when you can tell the buds apart on the tree. Feel free to give me or Dan a call with questions.