How to Care for Hydrangeas
Expert tips, whether they’re in a vase, potted, or in the ground.
Hydrangeas are everywhere—whether they’re on your dining table, in a wedding bouquet, or the highlight of your garden, these beautiful, lush blooms are a classic. But like any other flower, hydrangeas can be a bit intimidating when it comes to growing and caring for them. We asked the experts for their best hydrangea care guidelines for any scenario—in a vase, potted, or in the ground.
- Examine the Blooms
When you’re choosing your hydrangeas at the store, look for healthy, bright green leaves with bouncy blooms. “Check for any browning spots on the petals, which would indicate sun damage,” says Callie Bladow, production director at BloomThat. “Also, due to cold storage of cut flowers, keep an eye on dark petals which could indicate the blooms have touched the side of a refrigerator. You want a flowering hydrangea that feels sturdy and not soft or spongy.” If you choose a healthy bouquet, it should last up to two weeks.
- Use Your Garden
If you’re lucky to have garden hydrangeas, it’s easy to bring them indoors for a beautiful arrangement. Using a sharp floral knife or clean kitchen sheers, cut them on a bias (45-degree angle) and place them in a bowl of lukewarm water while you’re working outside. “The best time of the day to cut your hydrangea blooms is in the morning,” Bladow says. “Choose the most mature and full-looking blooms and leave the others to keep blooming. Fully-bloomed hydrangeas will look more ‘papery’ than the young-budded blooms.”
- Prep Them
Hydrangeas produce a sap at the bottom of the stems that needs to be sealed off so they can soak up water. “After you cut the stem on a bias, dip the stem in alum powder, which is an onion powder that you can pick up at your local grocery store in the spice aisle,” Bladow says. “All it takes is a simple dip of the bottom of the stem and then straight into the vase.” If you don’t have alum powder, you can dip the stem in boiling water for about 10 seconds, which will produce the same effect. You’ll also want to remove the leaves from the stem, since they’ll hog all the water in the vase.
- Get Creative With Arranging
You can go with a classic all-hydrangea arrangement, or experiment with mixing in different flowers or using unique vases. “I love using glass apothecary jars that have larger bases and small vase necks,” Bladow says. “The other way that we love designing with hydrangeas is to use them as grids for other flowers. There are multiple stems on the hydrangea head that keep other flowers secure, so just stick them into the flower head.” You can arrange with all types of flowers—she recommends roses, dahlias, and freesia, with some greenery like lemon leaf or variegated pittosporum.
- Provide Some TLC
“Hydrangeas like cool water and it should be changed every other day with a fresh snip of the stems,” Bladow says. “You can use the boiling water trick again after you cut them to increase vase life, or add in a little flower food or simple cane sugar from your pantry in the vase.” Make sure to keep your arrangement out of direct sunlight. And if your flowers are looking sad, Bladow suggests soaking the entire hydrangea in cool water for about 45 minutes—then shake them off, cut the bottom of the stem, and place them in water with flower food. It might help revive your hydrangeas and increase their shelf life.
- Know When to Plant Them
“The best time to plant hydrangeas is when temperatures are mild in spring and fall,” says Ryan McEnaney, a spokesperson for Endless Summer® Hydrangeas. “In spring, wait until you’ve passed your final frost and the ground is thawed enough to dig easily. In fall, be sure not to wait until late, when a frost could damage the plant.” If you want to plant in the summer, avoid doing so on very hot and bright days. These blooms are at their peak in mid-summer through fall.
- Choose the Right Location
Hydrangeas grow best in partial shade areas. “Make sure that there is enough space for the hydrangea to grow into, that the soil is amended as needed, and that there is the proper amount of sunlight,” McEnaney says. He recommends placing the hydrangeas in an area that gets about five to six hours of morning sun, followed by dappled (or patchy) shade. If you live in warmer regions, plant where the blooms can get two to three hours of morning sun and partial shade in the afternoon.
- Plant Carefully
“Dig a hole slightly larger than the pot your hydrangea came in, keeping in mind that you want to leave enough space in the garden for the hydrangea to mature to its full size,” McEnaney says. “Add a small amount of high-phosphorus fertilizer to the bottom of the hole, then remove the plant from its container and slightly loosen the roots with your fingers. Place the plant in the hole, making sure that the crown of the plant (where the base of the stem meets the soil) is even with the ground level.” After you put the hydrangeas in the ground, cover with soil and water. Hydrangeas prefer loamy (mixture of sand and silt with a bit of clay) and moist soil, so make sure you frequently check it in the beginning to ensure that it isn’t dry or soaking wet.
- Opt for a Shrub, Instead of Seeds
It’s okay to cheat and buy a shrub from your local gardening center, instead of trying to grow your hydrangeas from a seed—especially since seeds are hard to come by. “If you’re able to obtain seeds, you must sow or scatter the seeds in the soil, taking extra care until they’re germinated,” McEnaney says. “To get the same size shrub as you would in your local garden center, it could take 2-3 years.”
- Don’t Forget to Water Them
These flowers love water—so you’ll want to keep them hydrated. “One common misconception, though, is that they need constant water,” McEnaney says. “You want to ensure that the soil is moist, but not wet. Overwatering can actually cause the plant to grow without flowers. It’s better to give it a heavy soaking once a day (or whenever the soil needs it), preferably in the morning or early afternoon, than various applications of less water.” To find out if you need to water the plant, stick your fingers into the soil about an inch or two deep to see if it feels dry or wet.
- Give Them Some Extra TLC During Winter
Along with pruning dead stems and blooms, you’ll want to protect your hydrangeas during the winter. “Add an extra layer of mulch, leaves, or pine straw up to six to eight inches high to provide tender buds protection from drastic temperature changes, cold nights, and high winter winds.” McEnaney says. “It’s sometimes helpful for younger plants to add a cage to add more protection—and keep the bunnies out.”
- Choose the Right Pot
“Make sure that the bottom of your container has holes to allow excess water to flow though,” McEnaney says. “If there’s no drainage and too much water collects around the roots, it can prevent blooms from developing and cause the leaves to wilt.” For pot size, it ultimately depends on how many hydrangeas you want to plant inside and if you want to use any other kinds of flowers. With larger containers, because they hold more soil and more water, you won’t have to water them as frequently.
When it comes to the planting process, it’s similar to what you would do with in-ground hydrangeas, but you’ll use pre-mixed, bagged potting soil. “Fill the decorative container with potting soil, leaving roughly eight inches open on top,” McEnaney says. “Place the hydrangea in the center of the container and fill with soil.” Leave one inch of space between the soil and top of the container so nothing will overflow when you water the plant. If you have a larger container, you can also mix in other flowers for a colorful accent.
- Don’t Forget to Water
Like in-ground hydrangeas, the ones in planters need a lot of water too. To determine if your flowers need water, you can use the same method of sticking your fingers in the soil to gauge dryness. McEnaney advises that container hydrangeas might need more water since they’re not established in the ground and have less soil to soak up the water.