blue hydrangea white picket fence
Garden

Pro Tip: Hydrangeas + Alum

How to make summer’s hydrangeas last longer.


Hydrangea, literally means hydrate and cutting its stems on a slant helps that to happen. BUT nature provides instant sap sealer to preserve the hydrangea. So unless you remove the sap, the stem cannot take up ANY water, hence the wilting. There are over a dozen methods for reviving cut hydrangeas online and I’ve tried them all, however this method works the best.

Yes, I know you went to Ralph’s or Whole Foods or Trader Joe’s and purchased hydrangeas in cellophane. You brought them home, cut them, put them in warm water — perhaps with other flowers — and hoped for the best. Six hours later the hydrangeas were badly wilted. BYE-BYE. I’ve been there. I have spent from $6.99 to $18.99 for nice hydrangeas in pink or blue, white or purple only to have this sad result.

Pro Method:

Pick the freshest flowers from Costco, Whole Foods; ideally the same day they arrived.

  1. Buy a small jar of McCormick Alum

    Alum (potassium aluminum sulfate) is a food additive (spice) that is ideal for pickling and canning. It helps create crisp pickled fruits or vegetables. You can find Alum at Walmart and Amazon.com and some supermarkets.

    Pour a few tablespoons of Alum in a small bowl and set aside.

  2. Cut your hydrangea

    Take your bouquet, cut 1 stem on a slant with sharp pruning shears, reducing the stem length to 12 inches. Please do not crush hydrangea stems with a hammer. That works for lilac and cherry blossoms and forsythia only!

  3. Dip the stem in the Alum

    Immediately following your trim, dip the stem immediately in the Alum powder.

  4. Have your vase with lukewarm water ready

    Once you dip in the Alum, place your cut stem in your vase and leave them alone.

  5. Store in a dim place

    Hydrangeas need adjustment, place them in a dim place for several hours. They will be fine.

  6. Adding other flowers

    You can add flowers to this arrangement. However, I do not suggest roses as they need a different treatment to keep their heads from drooping.

Hydrangeas need to be added to water quickly.

Other Methods:

Wait until fall when the hydrangeas are papery but still have color – not brown. Cut the stems from the bush with pruning shears. Each stem should be about 18 inches. Bring inside and cut each stem to 12 inches. Dip in the very hot water and then put into vase — No alum needed.

Cut and dip immediately in boiled water and place in a vase. This method works best for fresh cut hydrangeas from your garden.

See my post on flowering bulbs. For more floral ideas see our La Soeurette Guide