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Archive for the bloom tag

Why won’t my hydrangeas bloom?

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I planted 2 Endless Summer hydrangeas and they bloomed beautifully. Over the next 2 years, I planted 4 more in a row next to the 2 originals, and they bloomed well. Last summer, however, the first two (which are 3 times the size of the last two) had beautiful, healthy foliage but absolutely no blooms. There were a couple of buds just forming in late August. Any suggestions to get the originals to bloom again this summer?

Endless Summer hydrangea (H. macrophylla) is a remontant (everblooming) variety. There is the initial late spring flush followed by sporadic blooming through the growing season. It blooms on both old and new wood growth. Wonderful attributes, if managed properly. In the North, these hydrangeas like full morning sun and afternoon shade from heat. Make sure the plants are getting about 5 to 6 hours of sun. Check that a tree or outbuilding isn’t shading them more than necessary.

Lack of bloom and robust foliage can indicate too much water and too much nitrogen-rich fertilizer. Check your watering practices. Water thoroughly but less frequently. They like rich, moist soil, but not saturated soil. A quality, slow-release granular fertilizer applied once in spring or early summer should suffice for these acid-lovers.

Be careful when and how much you prune. Don’t cut them back to the ground like the old-fashioned ‘Annabelle.’ Endless Summer does bloom on new wood, but if you severely prune them, you lose the benefit of old wood flower buds. The few buds you saw forming in August is how long it took the new wood to catch up. Review and adjust your maintenance practices, and you should have a better bloom season on the originals as well as the newer plantings.

Other posts about hydrangeas:

Why have my Hydrangeas changed bloom colors?

Healthy-looking rose bushes fail to bloom

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I have 6 rose bushes that get morning sun. The foliage looks great but I get no roses. I inherited these plants when I bought the house and I don’t know anything about them. I have good drainage and have given them rose fertilizer. C.M., Allenton

Your roses with no blooms are more than likely not receiving enough direct sunlight. In order to produce flowers, roses must have full sun, which is usually defined as a minimum of 6 to 8 hours of direct sunshine. Morning sun doesn’t sound like it fulfills that requirement. Perhaps the rose bushes have become shaded as the surrounding landscape has matured and trees and shrubs have grown larger, creating shade where there was once full sun. If that is the case you have two options.

First, it may be possible to prune back the offending trees or plants that are creating the afternoon shade, thereby allowing more sunshine to the roses. In a mature landscape that can be difficult due to the probable destruction of the aesthetics provided by the larger plants. A second and more viable option is to simply transplant the roses to a new space with the full sun they need. The best time to transplant roses is in the very early spring, while they are still dormant, before any new leaves have sprouted. You can get a jump on the process by digging and preparing the new rose bed this growing season in anticipation of the big move. Then, next spring, dig each bush with the largest root ball you can handle and move them into the light.

Steps for healthy blooming hydrangeas

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How can I get ‘Nikko Blue’ hydrangeas that
have not flowered in years to bloom?

Hydrangeas are colorful flowering shrubs that aren’t bothered by pests or diseases, and can bloom for weeks at a time. The reason the flowers go on for so long is that the showy parts aren’t flower petals at all. They are colorful sepals that are sterile, but showy so that they attract pollinating insects. The fertile flowers, usually found in the center of the cluster, are quite small and inconspicuous. The sepals can’t be pollinated, which means they don’t go to seed, and that’s what prolongs the “flower” show.

Hydrangeas thrive in part-shade and prefer a moist, woodsy soil enriched with peat moss and leaf mold. For best success, water them well throughout the growing season.

Two words to remember when it comes to hydrangeas that refuse to flower is “too much.” Although hydrangeas grow well in some shade, too much shade can result in gorgeous leaves and no flowers. Another problem could be too much fertilizer, specifically high nitrogen fertilizer. This again will give beautiful leaves but few, if any, blooms. Use a balanced fertilizer such as 16-16-16 at the time they start to bloom. Too much water or too much dryness can also result in lack of flowers.

Most big leaf hydrangeas (H. macrophylla, also called “mopheads”) bloom on the previous season’s growth (old wood) and are reliably hardy to hardiness zone 6. In Michigan it is advisable to protect mophead hydrangeas to ensure bloom. The old wood of the hydrangea must survive in order to get blooms the following summer. ‘Nikko Blue’ is a mophead type that for many years was one of the few relatively hardy big-leafed types available. However, many gardeners protect it in early winter by stuffing fallen tree leaves around the shrub and covering it with an upturned bushel basket or burlap.

The choice of location is very important: place them close to the house, on the north or east side. The south or west side would expose them to afternoon sun, which is too hot in the summer and increases the chance of bud damage in the winter. In addition, unseasonably low temperatures after a mild winter also cause a lack of blooming on big leaf hydrangeas. If the plant is actively growing and hit by a late spring or early winter frost, the buds freeze and the hydrangea won’t bloom.

Another common reason why macrophylla hydrangeas don’t bloom is improper pruning. Again, most hydrangeas bloom on old growth (last year’s wood). If you prune too much old wood or you cut that wood too late, you won’t get blooms. These varieties set their buds after bloom in late summer, so spring pruning would remove that year’s flowers. The proper time to prune the flowering stems is soon after bloom, in late summer, back to a healthy pair of buds or shoots. The only pruning necessary in the spring is removing dead wood as new growth emerges.

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