Propagating hydrangeas from leaves is one of the easiest ways to double your stock. Simple cut leaves, dip in some rooting hormone, plant in vermiculite or sterile soil, and you'll have new plants in a few weeks.
You can propagate hydrangeas in water in a similar way to propagating hydrangeas in soil however using this method can lead to varying results. Propagating in water can lead to a weaker root system that might fail when moved into soil outside, however, this does not happen 100% of the time.
To take hydrangea cuttings, use secateurs to collect material from hydrangea stems and a knife to trim each cutting. Due to its woody nature, it's not possible to propagate a hydrangea cutting in water, so you'll need to insert them into a pot of gritty compost, instead.
Remove the lower leaves of the bottom two leaf nodes. The leaf node is where a leaf comes out of the branch. Most roots will form at that point. Dip cuttings in rooting hormone (this is entirely optional) and insert into damp vermiculite or sterile medium.
Hydrangeas are pretty flexible; they can be started from softwood cuttings (fresh new growth) taken in early spring, when the plant is just leafing out, or semi-hardwood cuttings (partly matured first year growth that may have developed a semi-woody base) in late summer.
If hydrangeas are fed more nitrogen than potassium, they may skip flowering and grow more foliage instead, and leaves that are larger. If you aren't sure whether nitrogen is causing the issue or not, test your soil.
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.
When to Take Stem Cuttings. Hydrangeas are deciduous perennial shrubs that grow and bloom throughout the spring and summer months. You can take cuttings any time from late spring after the plant has leafed out until early fall.
Rooting time varies depending on several factors, including temperature, humidity and the health of your parent plant. But most hydrangea softwood cuttings should root in two to four weeks. To test your progress, pull very gently on a cutting. You'll feel a slight resistance from delicate new roots.
Hydrangeas produce a “sap” that clogs their stems and blocks water from traveling up it to those gorgeous blooms. The boiling water helps to do away with the sap.
Dunk the heads of the hydrangeas right under the water. Leave them for at least 15 minutes or submerged overnight. When you remove them from the water, gently pat them dry with paper towels. Place in a vase filled with fresh water.
Place the hydrangea(s) in the vase filled with hot water. Let sit for a minimum of one hour and voila! Revived hydrangeas.
Most gardeners take their cuttings from the end of spring to the beginning of autumn. You can take cuttings later in mid-autumn, provided the hydrangea is still growing, but as the temperature drops, you may find the cuttings struggle to put down roots without a heat mat.
Starting at the faded bloom, check around each set of leaves going down the stem. At the first or second set of leaves, you should see buds. Snip the spent bloom off well above those buds.
Miracle-Gro Performance Organics Blooms Nutrition
This is an all-purpose blossom booster that's suitable for use on a wide variety of perennial and annual blooming plants, including hydrangeas.
Coffee grounds add extra acidity to the soil around hydrangeas. On a chemical level, this increased acidity makes it easier for the plant to absorb naturally occurring aluminum in the dirt. The effect is pretty blue clusters of flowers.
Though hydrangeas prefer protection from hot direct sun, too much shade can prevent them from forming flower buds. Ideal light conditions for hydrangeas are several hours of direct morning sun with afternoon shade, or dappled shade that allows plenty of bright indirect light.
To bloom, most hydrangeas require at least three to four hours of direct sunlight per day, ideally in the early morning or dappled sunlight in the afternoon. Locations with full afternoon sun are usually too intense. Both too little and too much sunlight can affect blooming.
It's best to start adding coffee grounds to the soil months before the blooming season begins, ideally in the late fall. You can repeat the process with your typical fertilizing schedule. With a little caffeine and a lot of patience, your hydrangeas should reward your efforts come spring with the boldest blue globes.
Most common hydrangeas prefer a partial sun location - ideally receiving sun in the morning hours and shade in the afternoon. The reblooming Endless Summer® Hydrangea series prefers part shade.
On a mature hydrangea plant, make a cut about 2 inches below a leaf node on a green, healthy branch that has not yet formed flower buds. Avoid older, woody stems. The cutting should be 6 to 8 inches long, overall.
To rejuvenate the hydrangea, remove up to 1/3 of the older living stems down to the ground each summer. This will revitalize the plant. If necessary to control the size of the plant, cut back before late July to allow for buds to develop. Usually the plant will return immediately to its former size.