A healthy hydrangea in a nursery pot can look spectacular, covered in flowers and glossy green leaves. Getting it into the garden is usually straightforward, but the location matters. Plant one in scorching dry soil or somewhere that collects hard spring frost and you may spend years wondering why it never performs like it did at the garden centre.
Hydrangeas are generally happiest in moisture-retentive but well-drained soil, with some shelter and a little protection from the harshest sun. The precise preferences vary by type. Before digging, check the plant's label so you know how big it will become and whether it flowers on old or new growth.
Identify the kind of hydrangea
Mophead and lacecap hydrangeas, including many Hydrangea macrophylla varieties, are familiar garden shrubs. Hydrangea paniculata and Hydrangea arborescens have different habits, sizes and pruning requirements.
Climbing hydrangeas behave differently again and need a suitable support and location. Do not assume a climber should be planted in the middle of an ordinary border.
The Royal Horticultural Society advises checking eventual height and spread when choosing. A variety that grows into a large shrub is not ideal for a tiny bed directly under a window.
Choose a good spot before digging
Light shade is a useful starting point for many shrubby hydrangeas. The RHS says they can tolerate a sunny position where the soil doesn't dry out excessively.
Avoid exposed frost pockets and positions battered by cold winds, especially for cultivars with vulnerable emerging buds in spring.
You don't need deep shade in every case. Some panicle hydrangeas tolerate more sun, while certain large-leaved varieties can struggle in full afternoon heat. Match the variety to your actual site.
Check whether the soil drains
Hydrangeas appreciate moisture but not roots sitting permanently in stagnant water. After heavy rain, observe whether the proposed planting area remains waterlogged.
If the soil is heavy clay, improving structure with suitable organic matter can help, although some hydrangeas tolerate clay well when drainage and conditions are reasonable.
Don't plant into a deep hole filled with loose compost in the middle of compacted soil that behaves like a bathtub. The surrounding soil must allow roots to spread and water to move.
Think about flower colour realistically
Some mophead and lacecap cultivars can produce blue flowers in acidic soils where aluminium is available, and pinker colours in more alkaline conditions.
The RHS explains that changing colour depends on both cultivar and soil chemistry. White-flowering varieties and many other hydrangea types do not simply turn blue when given a specialist feed.
If the precise blue shade matters, check your soil pH and the cultivar rather than repeatedly pouring products around a plant with a natural white flower.
Know the best planting season
In the UK, spring and autumn are generally good times to plant shrubby hydrangeas. The soil is often moist enough for roots to establish without the hottest summer stress.
The RHS also notes that container-grown plants can be planted at other times if conditions are suitable. Avoid frozen ground, very wet soil and particularly hot dry spells where possible.
If you buy a flowering hydrangea in midsummer, keeping it watered while you choose a suitable planting opportunity is better than forcing it into baking dry ground immediately.
Water the pot thoroughly first
Stand the plant in a suitable container of water or water it well in the pot before planting, following the nursery's guidance. A dry root ball can be difficult to moisten once buried.
Let excess water drain before removing the pot. Handle by the root ball rather than hauling the plant out by its branches.
If roots have circled tightly inside the pot, gently loosen them where appropriate. Avoid tearing away half the root system in an effort to make every root point outward.
Dig a wide, not excessively deep, hole
The RHS recommends making the planting hole approximately as deep as the root ball and around three times wider.
A generous width helps loosen surrounding soil so new roots can move out. Planting deeply can bury the crown and create problems with moisture and oxygen.
Place the plant into the hole and check its level before filling. The top of the existing root ball should sit roughly level with the surrounding garden soil.
Backfill and firm gently
Return the excavated soil around the roots, breaking apart large clods and removing obvious debris. Mix in suitable soil improver when the conditions call for it, but avoid making a tiny island of vastly different material.
Firm around the root ball with gentle pressure to remove major air gaps, without stamping the soil into concrete.
Check the final level once more. If the plant sinks into a hollow after watering, adjust as needed rather than allowing the crown to stay buried.
Water the plant in
Give the newly planted hydrangea a thorough watering so soil settles around the roots. Watch for water running away down a slope or pooling for a long time.
Keep an eye on moisture through the first growing season, particularly in dry periods. A shrub with lush leaves can lose moisture rapidly on warm windy days.
The RHS advises watering newly planted hydrangeas when there has been no significant rain for seven to ten days, with adjustments for conditions. Use the soil's actual dampness as your guide.
Apply mulch without burying stems
A layer of garden compost or other suitable organic mulch can help retain moisture and improve soil. Spread it around the rooting area rather than piling it directly against the main stems.
The RHS recommends leaving a gap around the base of the hydrangea when mulching, helping avoid unnecessary moisture against the crown.
Don't treat mulch as a substitute for watering during severe dry weather. It helps reduce evaporation but cannot create water that isn't there.
Planting in a container
Choose a large pot with drainage holes, suitable compost and enough room for the chosen cultivar's eventual growth. The RHS suggests compact varieties for containers.
Water pots more frequently during warm weather because their root volumes are limited. Periodically check whether the plant has become root-bound or needs repotting.
If your soil is alkaline and you're trying to maintain blue flowers on a suitable cultivar, a container with appropriate ericaceous compost may offer better control of growing conditions.
Don't prune a new plant indiscriminately
Many mophead hydrangeas form flower buds on older stems. Cutting every branch back hard at the wrong time can remove the following year's blooms.
Other kinds, including several panicle and smooth hydrangeas, flower on current-season growth and can be pruned differently.
Identify the hydrangea before following pruning advice. The RHS provides separate guidance for macrophylla, serrata, paniculata and arborescens types.
Protect young growth from late frost
Tender spring shoots may be damaged by a sudden frost even when the established shrub itself is hardy. A sheltered planting spot reduces some risk.
Use suitable horticultural fleece temporarily when a damaging frost is forecast, keeping it appropriately secured and removing it when conditions improve.
Don't assume frost damage means the plant is dead. Wait for healthy new growth and assess branches before cutting large sections away.
If leaves wilt after planting
Wilting can indicate dry soil, root disturbance or excessive heat. Check the moisture a little below the surface rather than automatically flooding the hole.
If the ground is waterlogged, additional watering may make the situation worse. If the root ball remains dry despite damp surrounding soil, you may need to water carefully around the original root mass.
Some older flowers will fade naturally as the shrub settles in. Prioritise healthy leaves and roots over keeping every purchase-day bloom perfect.
What a successful planting looks like
The root ball is level with the soil, the plant is firm but not buried, water drains appropriately and there is space for the mature shrub to grow.
A little early care gives the hydrangea the chance to establish. Choose the right position, water during dry spells and avoid unnecessary pruning until you know the type.