Trim your flower stems as usual. Before you put them in a vase, spray the flowers with hairspray, taking care to keep the nozzle far enough away that the force won't damage delicate petals. Don't overdo it: A light coat is better than weighing them down with hairspray.
If you are looking for an inexpensive dried flower preserving spray, consider using hair spray. Spray several light layers of hair spray over the petals to form a moisture proof seal.
Hanging Hydrangeas to Dry
Hydrangeas can be air dried in a vase or on a clothesline. Marzec prefers to hang her blooms using this upside-down method, which, in her experience, allows for the fastest drying time and a minimum of flattened petals for her customers.
Spray: Once your hydrangeas are fully dried, spray them down with aerosol hairspray (sorry, aerosol spray just works better than the pump spray kind…it just does).
Put Hydrangeas In Water Immediately After Cutting
As soon as hydrangeas are cut, the stems should immediately be put into tepid water. And adding a little bit of flower food to it would be a great idea too. Use a sharp knife or clippers to cut each stem on a diagonal and submerge!
The easiest thing to do is to pick up a jar of alum at the grocery store (in the spice aisle) and keep it on hand for your cut hydrangeas. As you cut the stems, dip them quickly into the alum jar and then plunge them into a vase or pitcher filled with water.
When you are arranging your hydrangeas re-cut the stem about an inch above the previous cut and immediately stick the bottom ½" of the stem in the alum to coat it, then arrange as usual. It's easy and works! No more wilted hydrangea blooms!
A pH of 7 is neutral, and household vinegar has a pH of around 2.4 (which is quite acidic). The theory is, applying diluted vinegar to the soil will lower the pH enough to change the color of your hydrangea blooms. This strategy will make the soil more acidic, but not for long!
Use vinegar diluted with water in a ratio of 20 parts water to one part apple cider vinegar. Water the plants along their base. Try not to get the vinegar-and-water solution onto the leaves, because it can burn the foliage.
To keep your dried floral arrangement from fading, place your arrangement in a shady space. Bright light and direct UV exposure can be harsh on delicate blooms. For an extra layer of protection, spray with an aerosol UV protectant from your local art supply store.
If you leave the hydrangea heads to dry on the shrub they can lose all of their color. If you cut the blooms too early they can wilt (as opposed to dry with the petals retaining their shape). In order to retain the most color, you will need to let flowers partially dry on the shrub first.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
This common household item is surprisingly effective at helping perk up plants and brighten blooms. For hydrangeas specifically, adding baking soda helps the plant retain more moisture in the roots. When this happens, the result is bigger blooms with more vibrant colors that last longer than they would otherwise.
Hydrangeas are one of those florals that take almost no effort to preserve—they dry in about two weeks' time and can last for up to a year. You can preserve hydrangeas in several ways, but the water-drying method is best for helping the flowers hold their shape and color.
Keeping the flowers out of direct sunlight will help them retain their color. The drying process will take about two to three weeks. Once dried, take down the flowers and spray with unscented hairspray for protection.
Hang fresh flowers upside down in a cool, dark location until they are completely dry (about two to three weeks). In a well-ventilated spot, evenly spray the surface of the flowers, making sure all the surface is covered, and keep a good distance between the hairspray nozzle and the flowers so they aren't damaged.
If your hydrangeas do get infected, you have several easy, effective, and homemade options. You can dilute either hydrogen peroxide or garlic oil in a spray bottle and spray it directly on the affected leaves.
Hydrangeas change colors based on the soil pH levels. Coffee grounds can change soil by making it more acidic, which causes hydrangeas to turn blue, while more alkaline soils make blooms pink.
Pickle juice is mostly composed of vinegar, which can help to lower the pH of the soil and make it more acidic, which can be great for plants like Hydrangea, Gardenia, Camellia, Azalea, Begonia, Impatiens, Rhododendron, Blueberry, Potentilla, Heather, Vinca, Clematis, Fuchsia, and Astilbe.
Treating Slugs on Hydrangeas
You can spray the plants with soapy water. Use a teaspoon of dawn or joy dish soap with a quart of water in a spray bottle. Spray the leaves, branches and the ground beneath the plant.
But hydrangeas are among the few plants that can draw moisture in through their florets, so it's possible to perk up wilted blooms by completely submerging them in water and letting them sit for a few hours to rehydrate.
EMERGENCY RESCUE FOR WILTING HYDRANGEAS
Then recut and place the stems into boiling water and then back into a vase of fresh water. They should revive in a couple of hours and live another day or two.