Hydrangea - planting and care

Scientific name: Hydrangea paniculata
Family: Hydrangeaceae (Hydrangea family)

Long after the summer flowers have faded, the panicle hydrangea continues to bring color and life to the garden. This makes it a reliable choice for those who want to extend the summer feeling. Technically, the flowering period is not very long, but the bracts (which we think of as the flowers of the plant) remain until the snow arrives – in many cases, throughout the entire winter. Several varieties thrive up to hardiness zone 5, making panicle hydrangea a great option for many Norwegian gardens.

Find your favorite among our panicle hydrangeas

It is easy to get lost in the world of hydrangeas. There are almost 200 different varieties in the hydrangea family, in various shapes and colors. Here are the most common ones:

The most common hydrangea. Botanically, it is the same plant used both as a garden plant and an indoor plant, but there are different varieties that thrive best either outdoors or indoors.

One of the most beautiful autumn shrubs in the garden. It blooms with cone-shaped flower clusters from late summer until the snow arrives. Often changes color throughout the season.

A beautiful shrub for late summer. Blooms with impressively large, round flower clusters.

A climbing plant that thrives in the sun, blooms in early summer, and develops beautiful autumn colors.

Panicle hydrangea actually has nothing to do with lilacs, except that its flower clusters resemble those of a lilac—and that both shrubs often have a wonderful fragrance. The flower clusters of the panicle hydrangea are characteristically cone-shaped. The color of the flowers varies depending on the variety, and many also gradually change color throughout the season—often from more or less white to more or less pink, but other color combinations also exist.

All plants should be placed where they have the best conditions to thrive. Panicle hydrangea thrives in both sun and partial shade. Sun provides the richest and most beautiful flowering, but the plant prefers some protection from the strongest direct sunlight. Panicle hydrangea does not like dry conditions. The easiest solution is to plant it in the ground, where access to water is better than in a pot. To cover the soil and help retain moisture, it can be beneficial to plant ground-covering plants around the panicle hydrangea, such as cranesbill.

Panicle hydrangea can be planted from early spring until the frost arrives in autumn. However, it is important that the plant receives regular watering during the establishment phase, so we recommend planting either in spring or autumn. During these seasons, rainfall is usually more frequent than in mid-summer, reducing the need for frequent watering.

You can also plant panicle hydrangea in a pot, but this requires a bit more attention—especially when it comes to watering. You should also consider that winter can be too harsh, and unfortunately, there is no guarantee that potted plants will survive the winter season. Even though panicle hydrangea grows slowly, the pot should be large and spacious to prevent the plant from drying out too easily. Leave the plant outdoors during winter, but if possible, place it under cover. It can also be a good idea to choose a variety of panicle hydrangea that is hardy at least one hardiness zone above where you live. For example, choose a variety that withstands H5 if you live in H4. This tip applies to most shrubs and trees planted in pots

Panicle hydrangea thrives in nutrient-rich, well-drained, and moisture-retaining soil with a slightly low pH. Mix the soil at the planting site with hydrangea soil or rhododendron soil.

Watering
Water generously and regularly. The soil should be slightly moist—neither too dry nor too wet. Although panicle hydrangea is thirsty, it is not a swamp plant and should not stand in water.

If planted in the ground, the risk of overwatering is minimal, as excess water will drain away. Water thoroughly, especially during the first six months. You can, for example, let a sprinkler run for about 2 hours, 2–3 times a week—less if it rains a lot and more if the weather is particularly hot and dry. Once the plant is well established, you can water less frequently.

If planted in a pot, you must monitor watering throughout the plant’s life—ensuring it gets enough water without drowning. A pot with drainage holes is essential so that excess water can drain out. Using an inner plastic pot is also a good idea, as it helps retain moisture.

Fertilizing
Fertilize once in spring with rhododendron fertilizer or acidic soil fertilizer, following the instructions on the product you choose.

Pruning
Leave the flowers on the plant through the winter, as they often look decorative with frost. Shake off snow from the branches to prevent breakage. When spring arrives, cut off last year's flowers and look forward to new blooms in late summer.

Additional pruning is not necessary, but since panicle hydrangea blooms on new growth, it can tolerate pruning if desired. You can trim branches that are longer than others or thin out older branches. This should be done in the transition between winter and spring

When choosing a panicle hydrangea, there are two important factors to consider: how much space you have and which hardiness zone you live in. The different varieties vary in height, ranging from 50 cm to over 200 cm when fully grown. Many varieties thrive up to H5, but not all. To ensure success, it is important to take this into account, but otherwise, the choice is mostly a matter of preference.

For most people, flower color plays a significant role. There are also varieties that have been trained into small tree-like forms. Here are some of our favorites:

Panicle Hydrangea ‘Limelight’ – Can grow up to 2 meters tall over time. It produces lime-green flowers that change color throughout the season to various shades of white, pink, and green. Thrives in H1 to H5.

Panicle Hydrangea ‘Silver Dollar’ – Reaches about 1.5 meters when fully grown. This variety has white flower clusters that gradually turn pink. Thrives in H1 to H5.

Panicle Hydrangea ‘Living Pinky Promise’® – A small panicle hydrangea that stays around 70 cm tall. The large flowers change color from white to deep pink during the season. Thrives in H1 to H5.

Panicle Hydrangea 'Switch Ophelia' – The perfect choice if you can't decide on a flower color, as it changes color four times! The flowers start out light green, then turn white, soft pink, and finally deep pink. This is also one of the most compact varieties, staying under 50 cm in height. Thrives in H1 to H3.

Find your favorite among our panicle hydrangeas

TIPS FROM THE GARDENER
Miriam Gysling, gardener with a special interest in potted plants in general and cacti and Philodendron in particular