Your Complete Guide to Hydrangeas




Hydrangeas are a deciduous shrub that can flower from spring through summer and oftentimes into fall. They quickly fill in and can become a showstopper within just a year or two of planting. There are several different species of hydrangeas that grow in our area and understanding the differences between the four different types can help you become a successful gardener and ensure that you plant a hydrangea in the right spot and prune at the right time for the best results.

Below you'll find a description of each species and a few examples of varieties that we have in stock this week. To see a full list of available hydrangeas, please reference our tree and shrub availability list.



HYDRANGEA ARBORESCENS, aka Smooth Hydrangea

This species is very adaptable and can handle a wide range of soils and moisture conditions. Native to North America, it's the most cold tolerant of the hydrangea species. No need to fuss with soil pH - the flowers stay true to their color. Prefers part shade or full sun. In the south, smooth hydrangeas can still bloom in areas where it receives as little as 4 hours - further north hydrangeas prefer increased hours of sunlight (6 hrs). These blooms make great cut flowers, or feel free to leave the blooms on the shrub to dry to add winter interest. Allow the shrub to establish for a couple years before performing any hard pruning. Trim down to the ground in early spring or not at all if you want a larger shrub in the landscape.



ANNABELLE

One of the oldest and most popular smooth hydrangea cultivars. This classic shrub has huge white round heads of flowers often blooming throughout summer. Known for its vigorous blooms on sturdy stems. Grows to 4-5' tall and 3-5' wide.


HAAS HALO

Blooms are more of a flattened shape with loose flowers that provide a delicate look. The larger individual flowers along the outside of the inflorescence are sterile and the smaller blooms in the center are true flowers and provide more value to pollinators than most hydrangea species. Grows to a height and width of 3-5'.



HYDRANGEA PANICULATA, aka Panicle Hydrangea

The easiest and most adaptable hydrangea to grow. They are sun-lovers and perform well in urban plantings. They can handle part-shade, but bloom best in sun. "Panicle" references the pyramidal or cone shaped bundles of blooms. Panicle hydrangeas are known for their long blooming times. Most panicle hydrangeas bloom white and as the flowers age they turn to shades of pink or red. If blooms are left to dry on the plant they will fade to a beige color and add winter interest to the landscape. All panicle hydrangeas, regardless of variety, can be pruned the same since they all bloom on new wood - pruning should be done in winter or early spring and will ensure that blooms each summer.



LIMELIGHT

Known for the chartreuse green blooms in midsummer that fade to white and then shades of pink to burgundy in fall. Painters carries "Limelight Prime" which is an improved variety with a more compact stature (4-6' tall and wide) with an earlier blooming time and stronger stems to support the large heads of flowers.


LITTLE LIME

A dwarf variety of Limelight growing only 3-5' tall and wide. This is a great option for a lower height mass planting or in containers.

HYDRANGEA QUERCIFOLIA, aka Oakleaf Hydrangea Named after the leaf shape, oakleaf hydrangeas are the most heat tolerant of the hydrangea species that grow in our area. Another native to North America, this species blooms a little later than the other hydrangeas, but makes up for it by offering rich maroon red leaves in the fall. This is the one hydrangea I would hold off on pruning, unless it's necessary to prune out dead stems. This is a multi-stemmed, suckering shrub that often grows wider than tall. Looks great along woodland edges or in a natural/non-formal garden. Because oakleaf hydrangeas bloom on old wood, planting in a spot where it may have some winter protection can help save next-season's flower buds. This hydrangea prefers a little more shade, but can tolerate full sun. As the shrub matures, older stems exfoliate to reveal a rich brown inner bark that is attractive in winter.



QUEEN OF HEARTS

A hybrid of 'Snow Queen' and 'Pee Wee' varieties, matures to 6' tall and 9' wide. Noted for its large, upright conical flower heads (up to 9" long) which open white and gradually turn a deep pink.


SNOWFLAKE

Flower heads are formed with clusters of double blooms, resembling snowflakes. Bloom season is much longer than single flower species as florets continue to open throughout summer. Grows up to 6-10' tall and wide.

HYDRANGEA MACROPHYLLA, aka Bigleaf Hydrangea This is the most common garden hydrangea shrub, also called French hydrangeas. This species is showy and popular and there are two different types of blooms, lacecap or mophead. Mopheads are the shrubs that bloom large, dense, pom-pom-type flower clusters. This group has the ability to change flower color based on soil pH. (Click here to dig deeper on an explanation on how soil pH controls bloom colors in Bigleaf Hydrangeas).

Lacecap shrubs form flattened, round flower heads of tight fertile buds, resulting in an airy, delicate look. Bigleaf hydrangeas don't fare too well with hot summer afternoons, they may respond to the heat by drooping their leaves. Since blooms appear on old growth wood, make sure to plant in a spot where they have some winter protection.


ROSY SPLENDOR

Lacecap hybrid providing a head of double blooms - this variety can turn a soft blue if grown in acidic soil, but is known for its bright pink blooms. Grows to 4-5' tall and wide.


NIKKO BLUE

When planted in acidic soil, blooms have a beautiful Dutch blue coloring. Offers great cut flowers and makes a great statement in the garden, especially if planted along fences or as a border. Reaches 4-6' tall and wide.



PLANTING

The best time to plant hydrangeas is in fall, the second best is in spring. The idea is to give the shrub plenty of time to establish a healthy root system before blooming. The best time of day to plant is in early morning or late afternoon to protect the plant from heat stress. Please refer to our Tree and Shrub Planting Guide to better understand hole size and depth as well as proper mulching. Hydrangeas prefer evenly moist, well-draining soil. If you have heavy clay soil, make sure to amend the site with compost and plant the shrub shallow/mounded to promote better drainage. Mulch will help keep hydrangea roots cool and moist. Make sure to choose a planting site that will suit your hydrangea - Most all hydrangeas like warm morning sun and some afternoon shade.



WATER

Bigleaf and smooth hydrangeas require more water, but all varieties benefit from even moisture. Water hydrangeas deeply in the morning (sometimes needed up to 3x a week while the plant is getting established). Deep waterings promote root growth.


PROPOGATION

Do you have a hydrangea in your landscape that is a great performer or is sentimental? Do you wish to slowly build out a border in your landscape? Here are some techniques to help you save money and try your hand at asexual propagation!

  • Panicle and Bigleaf hydrangeas are propagated best through "layering". In early to midsummer, dig a small trench near your hydrangea plant and bend a branch down to the trench so the stem makes contact with the soil. Make sure 6-12" of the branch is extended past the trench. Make scratches on the bark where the branch touches the soil and back fill the trench with soil and place a rock on top to hold the branch down. With time, the branch will form its own root system and can be separated from the main plant and transplanted.

  • Oakleaf and Smooth hydrangeas put out new shoots through underground stems. Dig up the new young plant and carefully separate it from the main plant then transplant to a new location.


FERTILIZER

The best way to determine your fertility needs is by using a soil test, but the basic rule of thumb for fertilizing hydrangeas is as follows:

-Bigleaf prefers several light fertilizing applications in March, May and June

-Oakleaf and panicle do best with two applications in April and June

-Smooth hydrangea only need fertilizer once, in late winter

PRUNING

Both Bigleaf and Oakleaf Hydrangeas bloom on old growth, if pruning is necessary to promote fullness or maintain size then prune in late summer after the shrub has finished flowering. Make sure your pruning cuts are made just above a node (where a bud or lateral stem is present on the branch).

Panicle and Smooth Hydrangeas bloom on new growth, if pruning needs to be done it should be done in late winter. Smooth hydrangeas can be cut all the way back to the ground.

HYDRANGEA TYPE

WHEN TO PRUNE

FLOWERS APPEAR

Bigleaf (H. macrophylla

Summer, after flowering

On old growth

Oakleaf (H. quercifolia)

Summer, after flowering

On old growth

Panicle (H. paniculata)

Late winter, before spring growth

On new growth

Smooth (H. arborescens)

Late winter, before spring growth

On new growth

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