Q.Not Blooming Endless Summer Hydranges
Last year one of my Hydranges didn’t bloom at all, one had just 3 blooms & the other had tons of flowers. This year looks to be the same,can I do anything to get them to bloom?
I am assuming that all three cases (no blooms, some blooms and lots of blooms) were cultivars of the Endless Summer Series planted in the ground. ES is a hydrangea that can produce blooms from old wood (stems that were alive in 2020; flower buds would normally start to grow in late Summer 2020 or early Fall 2020) as well as from new wood (stems that begin to grow in Spring 2021). In Il, old wood normally does not survive winters so most bloomage comes from new wood. As soon as the new Spring 2021 stems get tall and old enough by Summer 2021, the stems will develop flower buds that will open right away. If the plant is not getting sufficient sunlight, moisture or nutrients, the stems may not get tall and old enough to produce blooms. When this occurs in places with a small number of hours of sunlight, you may want to consider using a reblooming hydrangea from the Let's Dance Series instead as their reblooming hydrangeas are more compact than the Endless Summer Series.
Hydrangeas may also slowly slow down or stop bloom production when they receive too much fertilizer, if you use a high nitrogen fertilizer or if lawn fertilizer typically falls near the hydrangeas. Fertilizing in IL: you should be fine with a single, annual fertilizer application in Spring. You can use either a cup of cottonseed meal, compost manure or organic compost. You can also use a general purpose, slow release, chemical fertilizer per label directions once in Spring; look for a chemical fertilizer with a NPK Ratio around 10-10-10 that also includes minor nutrients., as long as it is one of those suggested fertilizer types mentioned above. Feel free to use liquid seaweed, liquid fish or coffee grounds during the rest of the growing season but stop all fertilizers by the 2nd/3rd week of July (three months before your average date of first frost). Hint: provided that your soil has no nutrient deficiencies, you can use a fertilizer until the plants have become established in the garden. Then discontinue fertilizing but maintain 3-4” of organic mulch up to or past the drip line. The hydrangeas will then feed off the decomposing mulch.
Hydrangeas can be nibbled by pests like deer, bunnies and squirrels. If these guys tend to visit you, you may want to use a spray like Plantskydd. It is similar to Liquid Fence but Plantskydd does not need to be reapplied after it rains. Deer for example, may nibble on one hydrangea and skip the next one besides.
Pruning of live wood must be timed such that it does not interrupt the flower bud development and opening process. It is appropriate to remove all the dead stems (from last year) that have not leafed by the end of May but do not prune the new Spring 2021 stems. Typically, pruning of hydrangeas is not necessary or recommended if they are planted where they can attain their estimated size at maturity in the plant label.
In some extreme northern locations, very late frosts may kill the flower buds inside the new Spring 2021 stems but not kill the stems themselves. Frost protection and fertilizing after the 3rd week in May (note: that is your avge date of last frost in Kewanee) may help with this.
If the plants are grown in pots, avoid letting the potting mix become dry as the plant can abort flower buds if the soil becomes sufficiently dry.