Will My Peach or Cherry Trees Bloom This Year? Understanding Flower Bud Loss in Marginally Hardy Stone Fruits

Peaches and sweet cherries are often planted because of the appeal of high-quality, home-grown fruit. However, these crops are considered marginally hardy throughout Iowa, and their long term reliability is especially questionable in the northern part of the state. 

When these trees fail to bloom, many growers ask the same question: Why didn’t these trees flower? In most cases, the trees did form flower buds, but something prevented those flower buds from surviving until spring. If you want to check on your potential crop in advance, it’s important to check your buds while they are dormant to determine if winter temperatures caused damage. 

Fruit flower bud formation

The flowers that may be on fruit trees this spring developed in buds last summer. On most fruit crops, flower buds are more plump than vegetative buds (buds that will develop into shoots). Peach flower buds are only on one-year-old wood and are commonly the 2 outside buds at nodes that have 3 buds, but they can also be solitary (Figure 1). On cherries, most flower buds are on spurs on older wood, with a few non-spur fruit buds near the base of one-year-old wood (Figures 2 & 3). 

Checking for winter damage: cutting flower buds

When checking for winter damage be sure to sample a representative set of branches, or branches that represent wood that would be left after pruning. If damage-inducing cold temperature occurred recently, allow the branches to thaw overnight indoors before checking the buds. Compared to apples, peaches and cherries are relatively straightforward to assess for winter injury because their buds only contain flowers, not a mix of flowers and leaves. 

 When cutting buds use a very sharp blade (razor or utility knife). It can be challenging to get the proper cutting depth on your first few attempts. Cherry buds are often cut horizontally, while it may be best to cut vertically through the center of peach buds. If you cut too high or low horizontally, you may miss the damaged tissues (Figure 4).

How to recognize bud damage

Interior browning indicates that the flower pistil (reproductive portion of the flower) is no longer viable (Figure 5). Since cherries have multiple flowers per bud (Figure 6), it’s possible that some flowers within the bud may be viable and others are not. 

Why can there be bud damage in a relatively warm winter?

At our example location, the peach buds we sampled had around 30% live buds, while the sweet cherries had few viable flowers. Why? The peaches and cherries did not undergo relatively extremely cold temperatures for Iowa. The coldest recorded temperature for the winter at the nearest weather station to this location was -13F (Table 1), which often does not induce a large amount of damage. View a short video on checking peach and cherry buds for winter damage.

While our minimum low temperature this year was not extremely low, we received unseasonably cold temperatures in early December. Generally, woody fruit crops do not gain their maximum hardiness until winter. So, it’s possible that this damage occurred in early December when these buds were still adapting to the winter and had not achieved maximum hardiness (Figure 7). 

Implications of bud damage

Peaches and cherries don’t need all their flowers to set a full crop. Peaches only need roughly 10% of flowers to set fruit for a full harvest, while sweet cherries need around 20–60% of flowers for a full harvest. Selective pruning also removes the poorer quality wood and leaves high quality wood that is likely to have less bud damage. Even if you have significant bud damage, annual pruning of fruit trees is recommended. 

Keep in mind that damaged flower buds may still bloom in the spring, depending on when injury occurred. Don’t assume blooming means viability, cutting open flowers confirms whether pistils are alive, which is required for fruit formation.