Cornell Cooperative Extension in Tompkins County (Published September 2010)
There could be a number of causes for hydrangeas not to bloom. Since we can grow five different species of hydrangeas, some explanations vary based on which type it is.
But first, let’s cover the broad causes. The bush might not be fully developed for blooming. The majority of woody plants don’t bloom until they are rather mature. If a newly planted bush had flower buds when it was in a pot, it might bloom the first year. However, after that, it might not bloom for a year or two as it gets used to the soil in its new position. Instead of flower buds, it is actively forming new roots and branches. There will be a lot more flowers when it eventually starts to blossom again because the bush has indeed “bushed” out!
Sadder still, it’s possible that deer have devoured the flower buds. Where deer have pulled the buds off because they lack incisors, look for rough torn stem ends. Additionally, because all hydrangeas require moisture to thrive, blossoming may not take place if a drought strikes at the incorrect time.
The timing of some hydrangea pruning by gardeners has been off. At this point, determining the species becomes crucial. We have two species that flower on fresh wood (new growth of the current growing season). These include the panicle hydrangea, Hydrangea paniculata, also known as the PG hydrangea, which is frequently seen densely planted in cemeteries, and the native smooth hydrangea, Hydrangea arborescens, which is frequently sold under the cultivar name “Annabelle” and typically has white mophead flowers. Early spring is a good time to prune these two species, and the new growth will bloom later in the summer.
Our other three hydrangea species, however, only flower on aged wood (growth from the previous growing season). The native oakleaf hydrangea, Hydrangea quercifolia, with stunning crimson or maroon fall foliage color, the climbing hydrangea, Hydrangea anomala petiolaris, a fantastic vine for partial shade, and the majority of the highly popular blue or pink bigleaf hydrangea, Hydrangea macrophylla, are included. The flower buds will probably be removed if these plants are pruned in the fall or early spring. It is preferable to prune immediately following blooming, before the new flower buds emerge.
The bigleaf hydrangea has undergone a number of new types over the past few years. They bloom on both old and new wood, hence the name “remontant.” Growing these types will help one prevent a further cause of poor bloom. Flower buds on older, non-remontant types of Hydrangea macrophylla frequently die in our cold winters. However, gardeners who reside in urban areas or close to bodies of water, where the winters are less severe, frequently have success with these types. A winter with a thick layer of snow may also adequately shield the flower buds from the cold in rural areas.
Many customers ask why their hydrangeas aren’t blooming. The primary reasons hydrangeas don’t bloom are incorrect pruning, bud damage due to winter and/or early spring weather, location and too much fertilizer.
There are hydrangea kinds that bloom on either fresh or old wood, or even both. Both new and old wood are the growth of the following year (spring), respectively.
- Consider that this year, you bought a Nikko Blue Hydrangea. For the next year, Nikko’s produce blooms in the fall. Your Nikko is therefore creating blooms this fall that will blossom in the spring.
- Therefore, you wouldn’t want to completely prune your Nikko Blue Hydrangea this fall while you are pruning your perennials. Pruning the Nikko Blue Hydrangea this fall would effectively mean cutting off your hydrangea flowers for the upcoming spring.
- The idea behind Endless Summer, a hydrangea variety that blooms on both old and new wood, is that the plant will set blooms this fall to blossom not only in the spring of the following year, but will also keep producing blooms in the spring of the following year to extend the blossoms into the summer.
- Once more, pruning your Endless Summer hydrangea in the fall would mean removing some of the flowers that would blossom in the spring.
The hydrangea’s plant tag will indicate whether it blooms on fresh wood, old wood, or both. It is typically preferable to wait until spring to prune your hydrangeas. As the plant grows, you’ll see stems that are fragile when bent and lack any leaves. Since these stems are dead and won’t produce any flowers, they should be clipped close to the plant’s base.
The second reason why your hydrangeas aren’t blooming is probably the weather. Buds of hydrangeas are extremely susceptible to cold. Therefore, it is a good idea to wrap your hydrangea for the winter if it is an old wood hydrangea. Keep in mind that old wood hydrangeas establish their blooms for the following spring in the fall. Therefore, you won’t have blossoms in the spring if the fall-produced buds are frozen in the winter.
You can wrap anything with regular burlap. Burlap should be wrapped around the plant and filled with mulch or leaves after the first hard frost and after the hydrangea’s leaves have dropped. In order for the buds to survive the winter and sprout the following spring, the plant receives insulation from this. Never wrap your hydrangeas in plastic. When warmer winter days arrive, the plant cannot breathe since plastic, unlike burlap, doesn’t breathe. As a result, the plant can heated to such high temperatures that it cooks within the plastic and perishes.
The second most frequent weather-related cause hydrangeas do not blossom is late spring killing frosts. We saw really chilly temperatures in April both this year and last year after beautiful spring days. When springtime temperatures drop below freezing, hydrangeas need to be covered with an old beach towel or sheet. Because of the temperature dip, there won’t be any blossoms.
The majority of hydrangeas require at least 3 to 4 hours of light per day to bloom. The best light is in the early morning, midday light is acceptable if it is dabbled light rather than beating sun, and afternoon sun is typically too hot. Check the plant label, though. Newer hydrangea cultivars are being created that can withstand more sun exposure time and sun intensity. A hydrangea in full sun will require much more watering than one in diffused light, so keep that in mind.
High nitrogen fertilizer should not be used to feed hydrangeas. Nitrogen is indicated by the first number on the fertilizer ratio. (The ratio stands for N, P, and K) For healthy leaves and general good growth, some nitrogen (N) is required; however, a ratio of 8-16-6 or any similar combination with a higher middle or phosphorus (P) value is preferred. The growth of roots and shoots is encouraged by phosphorus, which improves the blooming process.
Potash (K), the third element’s last quantity and the lowest ratio, is for plant hardiness. Because hydrangeas prefer acidic soil, they can be fertilized with fertilizers designed for such plants. Hydrangeas only require fertilizing twice a year, once in early spring and once in mid-summer. To avoid root burn, make sure the soil is always moist before applying a fertilizer.
Does the first year of hydrangea bloom?
Grandma was difficult to persuade. Shrubs had to produce and need little care to survive in her garden. Smooth (Hydrangea arborescens) or mophead (Hydrangea macrophylla) hydrangeas in particular were appreciated because they bloom all summer long, unlike many perennials that fade in the heat, need little care, and produce dried pompoms for winter arrangements. Additionally, hydrangeas can bloom in your yard every year because they can be grown in USDA hardiness zones 3 through 9 depending on the variety.
Why doesn’t my hydrangea ever bloom?
All varieties of hydrangeas like regular soil moisture and a good deal of moisture. Your plants might not bloom if yours constantly dries out.
In a hot and dry area, bigleaf species plants could require watering every other day.
If you aren’t getting enough rain to meet the two inches of water per week that these plants require, you’ll need to supply additional irrigation.
You can use a rain gauge to determine how much moisture Mother Nature is providing your plants with so that you can provide the extra.
Though less erratic, other species should still be monitored to make sure they have access to enough water.
The leaves will begin to droop and wilt if they aren’t getting enough water, especially during the hottest part of the day.
If your hydrangeas aren’t flowering, what should you do?
You may have overpruned your hydrangea the year before if it won’t bloom this year. Hydrangeas that aren’t blooming have frequently had their branches cut in the early summer and late winter. They will tend to die back more quickly than usual if they are overpruned, and you will have to wait a full year for them to bloom once more.
The solution is to only prune your hydrangea in the early spring when the dead wood is visible. Once more, if you notice your hydrangea isn’t blooming, double-check the kind and keep track of when it died the previous year. Keep in mind that it might require the old wood for it to blossom.
Finally, you might want to have your soil tested if your hydrangeas are not blooming and you’ve decided that nothing in this article pertains at this time. Your hydrangea may have luxuriant green foliage but no blossoms if your soil is nitrogen-rich. Like many other flowering plants, hydrangeas require phosphorus to effectively bloom and flourish. A fantastic technique to boost the phosphorus in the soil is by adding bone meal. Additionally, bear this in mind as you select a fertilizer for your plants.
How long does it take hydrangeas to grow?
I’ll address some of the most typical queries about hydrangea plant care in this section. If you can’t find your response here, post it in the comments section and I’ll respond as soon as possible.
Are hydrangeas easy to care for?
Hydrangeas are indeed quite simple to maintain when given the proper growing conditions. They are resilient plants that require little maintenance and will flourish for many years.
How big do hydrangeas grow?
According to the variety. Dwarf species can grow to only a few feet tall, while larger ones can grow up to 15 feet tall. Always look at the plant tag to see the precise size that your chosen hydrangea will reach.
Can hydrangeas tolerate full sun?
In colder climes, certain hydrangeas may be able to endure a placement in full sun. To achieve the greatest results, it’s better to put them where they will receive some partial shade.
How long does it take for a hydrangea to grow to full size?
Hydrangeas take between two and four years to attain their maximum size, despite the fact that they are fast-growing shrubs. Some people mature more quickly than others.
Hydrangeas are easy to grow and are tolerant of almost any climate. The nicest aspect is that you can have a wide variety of those big, beautiful blooms all summer long because there are so many different species. Your hydrangeas will flourish for many years to come with the right care.
How do hydrangeas appear before blooming?
The tips of the stems that Big Leaf and Mountain Hydrangeas generated last year are where they blossom (old wood). Some of those same stalks also have flowers on the sides (new wood). Still other plants bloom on stems they create this year (new wood). The old wood plants need to cling onto those blooms for approximately nine months, through late fall, winter, and early spring, beginning around August 1. Therefore, if you prune the stems of your old wood plants after August 1, you run the danger of losing the flowers that will bloom the next year.
No Pruning After August 1st
First rule: don’t prune them until the buds start to show, which may not be until June. The buds resemble little broccoli heads. Then you will know which stems and buds successfully overcame their seasonal obstacles.
If your shrub isn’t blooming, the first thing you should look at is whether or not you pruned it back. These plants often only require trimming to remove damaged, diseased, or dead stems.
Are hydrangeas water-intensive plants?
Although the hydrangea’s leaves and flowers seem delicate, little careful care is actually needed for them. Everything you need to know about caring for hydrangeas is provided in these recommendations.
- Over the course of the growing season, water at a rate of 1 inch per week. To promote root growth, deeply water three times each week. All varieties of hydrangeas benefit from constant moisture, but bigleaf and smooth hydrangeas need more water. To water thoroughly while keeping moisture off the flowers and leaves, use a soaker hose. Hydrangeas won’t wilt as much if they are watered early in the day on hot days.
- To keep the soil around your hydrangeas cool and moist, add mulch. Over time, an organic mulch decomposes, supplying nutrients and enhancing soil texture.
- Apply fertilizer according to the type of hydrangeas you have. Every variety has varied requirements and will profit from applying fertilizer at various times. A soil test is the most effective tool for determining your fertility requirements.
- In March, May, and June, bigleaf hydrangeas require numerous mild fertilizer applications.
- Two applications in April and June work best for oakleaf and panicle hydrangeas.
- The only time smooth hydrangea plants require fertilizing is in the late winter.
- By selecting cultivars with resistant characteristics, you can avoid pests and diseases. Hydrangeas can have leaf spots, bight, wilt, and powdery mildew. Although they are uncommon on hydrangeas, pests might arise when the plants are under stress. Aphids, leaf tiers, and red spider mites are examples of potential pests. Your best line of defense is to properly care for hydrangeas.
Do hydrangeas like shade or the sun?
With the ideal balance of morning sun and afternoon shade, hydrangeas flourish. Even the sun-loving Hydrangea paniculata will thrive in some shade. Some hydrangea cultivars may survive complete shadow, though.
The oakleaf hydrangea, also known as hydrangea quercifolia, is a substantial species of hydrangea that may reach heights of up to eight feet. In a shade garden, this big bush makes a beautiful backdrop. The height will provide excellent midsummer seclusion. Oakleaf hydrangeas are summer bloomers with mostly white blooms, elegant oakleaf-shaped leaves, and lovely peeling bark.
Hydrangea anomala ssp. petiolaris is another choice for full shade. This climbing species, which has lacy, white blossoms in the summer, can reach a height of 50 feet if it is given adequate support. The foliage is a rich shade of green and would look wonderful growing up a tree trunk or covering the face of a building. It would also look lovely covering the roof of a garden shed.
Full shade cultivars require the same upkeep as partial shade. In the deeper shade, it will be especially crucial to keep the plants free of leaf litter and with excellent airflow. Water your plant once a week after it has become established. Keep a watch on the leaves, and if you notice any drooping, especially during the hot summer months, water them right away. The importance of this increases in hotter regions.
These leaves’ unique shape would be a lovely complement to Hosta leaves. The white blossoms would contrast nicely with the lighter hues of your shady blooms and provide some brilliant brightness to your shaded locations.
Shade Varieties
There are a few different hydrangea cultivars that thrive in the shade. Some types can even thrive in zones 3 (which doesn’t warm up until later in the spring), which is one of the coldest growing regions. Let’s examine some of the best shade selections!
Hydrangea quercifolia ‘Snow queen’
The movie “Snow queen” is stunning. The flowers are stunning, as they are with all hydrangeas. These rose blush-colored blossoms appear in the middle of summer. The foliage of this plant is my favorite component. The leaves begin the season in a very deep green, gradually changing to a deep reddish bronze color, and finally finishing in that shade, offering a stunning splash of color to your fall landscape.
Hydrangea quercifolia ‘Alice’
With a height ranging between 12 and 15 feet, this Oakleaf Hydrangea is one among the biggest. In the summer, this plant blooms with incredibly deep cream-colored flowers. A woodland garden would be a truly lovely place for “Alice.” This cultivar would look especially beautiful if it were grown as a bordering hedge.
Hydrangea arborescens ‘Annabelle’
‘Annabelle’ enjoys partial shade and has some of the largest flowers in the hydrangea family (12 inches wide!). These enormous blossoms can be supported all season long by the sturdy stalks. This shrub can grow up to five feet tall and five feet broad, so give it plenty of area to expand. These enormous, all-white blossoms bloom for a long time.
In a mass planting, as a specimen shrub, or as a foundation planting, “Annabelle” would look lovely. These bushes should still be included in your cutting garden. Imagine a bunch of flowers that large! Wow!