Thanks for reaching out to Ask Extension. I'm sorry to hear about the cherry trees. It is difficult for us to make a determination of what could cause small cherries, but if you could send us some images of the trees and maybe a description of the watering and fertilizing schedule that would really help. Were the trees that bore smaller fruit late to bloom? Is the area around the trees mulched? There are a lot of factors that could impact cherry size and production so I want to make sure we can give you an informed answer.

Looking forward to helping out,

Brody K

Colorado Master Gardener Apprentice

I’ve just had knee replacement surgery and I’m not very mobile, plus the cherries have been harvested in what was probably a maximum effort flurry of activity. The largest of the trees had the smallest of the cherries. The are fertilized using CSU’s guidelines and schedule. They are a mulched area, irrigation is by a drip system, 3 emitters for each tree, 1.5 gallons,once or twice a day. The owner is in the process of reworking the system hopefully to deliver more water in the future. I’m not certain if this helps. We have no complaints about the yield with around 250 lbs from 9 trees, just curious about the size difference. Thank You, this is a great resource.

Hi Robin,

Thank you for the detailed information. I agree, that the larger trees may have needed more water during this season's extreme heat. Several factors, including pollination, could have contributed to the smaller fruit size on your larger Montgomery cherry trees. Ensuring that there are compatible pollinator varieties nearby, such as Bing Cherry cultivars that bloom simultaneously, can enhance fruit set and size. It's great to hear you're proactive about the trees' nutrient and water needs. Have you considered the sunlight exposure for the larger trees? Proper pruning maintains an open canopy for sunlight and air circulation while thinning excess fruit early can encourage larger, healthier cherries. Lastly, regular monitoring for pests and diseases is crucial for managing any issues that might affect fruit development.

I hope this information helps you. Happy Gardening!

Nicole M.
El Paso County Master Gardener Apprentice