Mention hydrangeas, and most will immediately picture those big, puffy blue balls of blossoms on little shrubs with bright green, shiny leaves. That would be a bigleaf hydrangea. But the ubiquitous hydrangea is just the tip of the varied world of hydrangeas. Turns out there are six major types of hydrangeas, and to confuse the issue even further, care and pruning of those types can vary greatly.

And figuring out what to do and when to do it can be the key to hydrangea success. Growing hydrangeas is basically easy. Here in zone 5, most hydrangeas will tolerate full sun, though many will thrive in partial shade. (Full sun is six or more hours of direct sun, and partial shade means four to six hours of direct sun.) Hydrangeas prefer a slightly acid soil, and commercial fertilizers such as Holly Tone help provide that optimum requirement.

Different types of hydrangeas have different flowering habits. Some hydrangeas bloom on new wood, or stems that are newly grown each season, while others bloom only on “old wood,” that is, stems produced the previous season, and some bloom on both old and new wood. This makes it vital to understand whether and when to prune. Always keep those tags that accompany your hydrangeas so you will be able to positively identify which type you have, to enhance your variety selection and so you will always know the correct care for your vaariety. From the folks at Proven Winners, we have this cheat-sheet of hydrangeas:

Bigleaf: Also known as florist’s hydrangea, hortensia, mophead, or lacecap. Hydrangea macrophylla

Hardy to USDA zone 5

Blooms on old wood: do not prune, protect in winter

Proven Winners varieties include:

Abracadabra series, Cityline series, Edgy series, Let’s Dance series, Paraplu

Panicle: Also known as peegee hydrangea. Hydrangea paniculata

Hardy to USDA zone 3.

Blooms on new wood: prune in late winter/early spring.

Proven Winners varieties include:

Bobo, Fire Light, "Limelight," Little Lime, "Little Lamb," Pinky Winky, Quick Fire, Little Quick Fire, Ziinfin Doll

Smooth: Also known as Annabelle hydrangea. Hydrangea arborescens

Hardy to USDA zone 3

Blooms on new wood: prune in late winter/early spring

Proven Winners varieties include: Incrediball series and Invincibelle Spirit II

Climbing: Hydrangea petiolaris are hardy to USDA zone 4

Mountain: Hydrangea serrata

Hardy to USDA zone 5

Blooms on old wood: do not prune

Proven Winners varieties include: Tuff Stuff series hydrangeoides.

Oakleaf: Hydrangea quercifolia

Hardy to USDA zone 5

Blooms on old wood: do not prune, protect in winter

Proven Winners varieties include: Gatsby series

Panicle and smooth hydrangeas flower on new wood (growth created in the current season). Flower buds on these hydrangeas form after the plant leafs out in spring, and open a few months later in summer. As a result, these plants flower reliably each year, no matter how cold the winter was.

Bigleaf, mountain, oakleaf and climbing hydrangeas flower on old wood (growth created in the previous season). Flower buds on these hydrangeas begin to form in late summer and must remain undisturbed all through the fall, winter and spring in order to flower the following summer.

As a result, these plants will not flower if:

They are pruned. Pruning at any time will remove potential flower buds.

They are browsed by deer, which will eat the flower buds.

They are damaged by weather. Winter weather isn’t actually the problem; rather, it is in spring, when several days of warm temperatures are followed by a sudden freeze, that flower buds are most likely to be damaged.

Reblooming hydrangeas, also known as remontant hydrangeas, are types of big leaf and mountain hydrangeas that have the unique ability to flower on both old and new wood. Even if the buds are damaged in winter weather, the plant can still flower on wood it produces that season. Reblooming hydrangea varieties include the Let’s Dance series, and Tuff Stuff.

It is a lot to take in, but knowing how and when to prune your hydrangeas will ensure that you get maximum enjoyment and floral performance from them. Plant hydrangeas with full or partial sun exposure in rich soil. Provide adequate moisture and fertilize with an acid fertilize.

Now Mom will know how to care for that pretty hydrangea she got for Mother’s Day.