Apple trees will bloom in early spring between mid-April and mid-May after having met the required chill hours during winter dormancy. Apple tree bloom depends less on the time of year, and more on the temperature in your region.
In order to determine exactly when your fruit tree will bloom, it is important to understand the budding stage of apple trees.
In the first stage, the apple tree is dormant through late-fall and winter once temperatures fall below 45° F (7° C). During this stage, the buds on the apple tree are tight, with no visible green showing, and the tree is in a rest period. This is a crucial stage in the budding of apple trees, because without enough cold weather during the winter, your apple tree won’t bloom in the spring.
Why do Apple Trees Need Cold Weather To Bloom?
Each apple tree variety requires a certain number of hours during winter dormancy where the temperature is between 32-45 degrees F (0-7° C). The number of chill hours required ranges from 500-1000 hours depending on the apple cultivar. The chill period is crucial to apple trees in the fall and winter in order to break down the hormones for dormancy. Without enough chill hours, the apple tree will not produce flower buds in the spring, and your apple tree won’t bloom.
For example, a McIntosh apple tree will require 900 chill hours, while a Granny Smith apple tree will only require 400 chill hours, and is more suitable for areas with more temperate weather.
Once the required number of chill hours are met, the apple tree will enter the next stage of budding and start to produce silver tip buds. During this stage, the bud scales will start to separate, and fuzzy gray/silver tips will develop. Soon after, the buds will start pushing out green leaf tips from the buds once the weather is warm enough to take advantage of photosynthesis.
How To Identify Flower Buds On Apple Trees
There are two types of buds on apple trees – fruit buds and leaf buds. The fruit buds will turn into flowers, bloom, get pollinated (hopefully) and produce fruit. The leaf buds turn into leaves or shoots for next years fruiting buds. It is only in the spring once temperatures warm up that the apple trees growth hormones will determine whether the bud will become a fruiting bud or growth bud.
In early spring, look for signs of opening buds on the tree branches. This is a sign the apple tree is coming out of dormancy and using its energy reserves to push out new leaves and flowers through its buds. Once the buds start to develop, you can more easily identify which will be a fruiting bud and which will be a growth bud. Fruit buds are larger and more plump, while growth buds are smaller, lay closer to the branch and are more pointed.
Once the green leaf tips start to emerge, the next stage of the budding process is the tight cluster stage. At this point you should see small clusters of tiny green flowering buds in the centre of a cluster of leaves.
In general, once leaves start to appear on your apple tree and you start noticing tight clusters of 5-8 green fruiting buds, the flowers should start to bloom approximately 2-3 weeks later. Over the next week or so, the tight clusters of green fruiting buds will gradually turn pink. Keep an eye on the first bloom. Once the first flower blooms, full bloom will be imminent.
Full bloom could happen as early as mid-April in North Carolina, or as late mid-May in more northern climates.
How Long Do Apple Trees Bloom?
Once in the full bloom stage, the apple tree bloom will usually last 3-10 days, depending on the variety. During this time, bees and other insects will pollinate the flowers. 5-10 days after about 75% of the petals fall off the flowers and fruit will begin to set. Check the base of the flowers – if they are swollen, the flower was pollinated, and an apple will begin to grow.
Why Your Apple Tree Isn’t Blooming
For one, your apple tree may not have received the required number of chill hours during its dormant stage. If you had a mild winter compared to previous years, your apple tree may still be lying dormant, and hasn’t received the signal that spring has arrived.
A full sized apple tree will be mature enough to bloom within 7-10 years from the time it was planted in your yard (not from when it was seeded), while a dwarf apple tree can usually bloom within 2-3 years. This largely depends on the cultivar as well. McIntosh apples can bloom within 3-5 years of being planted, while Northern Spy will need 15 years before they start blooming.
Apple trees that have been heavily pruned, or excessively fertilized, will put energy into vegetative growth rather than reproductive growth.
Apple trees that produce a large crop one year, may produce very little the next. Developing seeds in apples emit plant growth hormones that inhibit flower bud formation the following year. Try thinning the fruiting buds once the petals have fallen off the flowers if you notice an unusually large number of fruit compared to previous years.
Apple trees require full sun to grow and reproduce. If your apple tree is planted in a shaded area dig it up and transplant it to another area of your yard.
How Can I Make My Apple Tree Bloom
There are a few ways in which you can induce your apple tree to bloom the following year.
Train The Branches Horizontally
In the spring, train the branches of your apple tree to be more horizontal, rather than vertical. Horizontal limbs encourage flowering buds, while vertical limbs favour vegetative growth. The following year, you should notice flowering buds on the newly trained horizontal limbs.
Score The Limbs
Using a sharp knife, score a single line about one-quarter inches deep around the base of the limb. This induces ethylene production, which is a plant growth hormone, and will encourage trees to induce buds. It also interferes with movement of carbohydrates out of the upper portion of the tree to the roots making more sugars available in the upper portion of the tree. The proper timing is from full bloom to about three weeks after full bloom. The following year, you should notice flowering buds along the scored limb.
By now you should know everything about the apple tree blooming stages and be able to identify each stage of your apple trees growth.
Are apple tree blossoms edible? Yes, the flowers on an apple tree are edible and are high in antioxidants and minerals. Dried apple blossoms can be steeped to make teas, aged in vodka, flavour jellies, or used fresh as a garnish. Read our post on apple blossoms to learn more.