Hydrangeas are such a beautiful addition to any garden. These shrubs are massively popular among green-thumbed homeowners and allotment visitors for their relatively low maintenance requirements, extended flowering periods and the impressive range of colours they can display. From the wider petals of bigleaf hydrangeas (macrophylla varieties) to the smaller flower clusters of petiolaris shrubs, gardeners have plenty to enjoy with hydrangeas. However, while pre-grown, potted plants do save time and effort, feeding them properly is still essential if you want healthy hydrangeas that reward you with big, beautiful blooms year after year.
This guide will offer you a tour through everything you need to know about fertilising hydrangeas – including the best fertiliser to use, the right time of year to apply it and even how to use feeding to influence the colour of your blooms.
You should start by finding and stocking up on the best hydrangea fertiliser. Luckily, there are products created specifically for fertilising hydrangeas, often sold as liquid or granular feeds. These are carefully balanced with the essential nutrients hydrangeas prefer:
Nitrogen – promotes healthy growth and greener leaves
Phosphorus – supports root development and helps hydrangeas bloom
Potassium – encourages strong, beautiful blooms
Iron and magnesium – combat nutrient deficiency and help maintain healthy plants
If you can’t find hydrangea-specific feeds, rose fertilisers or slow-release fertilisers developed for feeding woody shrubs are great alternatives. Even general garden feeds will do the job in a pinch, provided they are well-balanced and not too heavy on phosphorus, which can sometimes reduce flower output.
For gardeners who prefer a more natural approach to fertilisation, compost and well-rotted manure can provide nourishing organic matter. This supercharges nutrient levels, while simultaneously improving soil structure and aiding moisture retention – something hydrangeas always appreciate.
Hydrangea-specific liquid feeds
Slow-release fertilisers for shrubs
Rose feeds as a backup option
Organic matter, like compost or manure
The fertiliser you use is only part of the equation – timing is essential for healthy hydrangeas. Hydrangeas prefer seasonal feeding cycles that support new growth, flower production and recovery from harsher weather.
The best time to start fertilising hydrangeas is during the early months of spring, just as new growth begins. This sets up the plant for a healthy growing season and encourages abundant flower buds. Apply a balanced fertiliser at the base of the shrub, and water well.
A second round of feeding in early summer helps boost those beloved blooms and sustain healthy growth. This is particularly important for young plants that are still establishing themselves in your outdoor space.
Avoid feeding too late in the season. Fertilising hydrangeas in late summer or autumn can encourage fresh growth that won’t have time to harden off before the harshness of winter, leaving the plant vulnerable. Instead, switch to organic matter or mulch to protect roots and nourish the soil.
Fertilising hydrangeas is simple enough, but it still requires a degree of care and technique to avoid damaging the plant:
Apply the fertiliser around the drip line – this is the area directly under the outer edge of the branches, where feeder roots are located.
Avoid direct contact with stems and leaves – fertiliser touching leaves can cause chemical burns.
Watering hydrangeas after feeding – always water thoroughly after fertilising to help nutrients soak into the soil.
Check the dosage – more fertiliser does not mean more fertilisation. Follow the instructions carefully to avoid overfeeding.
Hydrangeas grown in pots or containers require more frequent feeding than those in garden beds, as nutrients wash out more quickly during watering. Use a slow-release fertiliser or liquid feed every 2-3 weeks during the growing season. Container hydrangeas also benefit from partial shade, as full sun can quickly dry them out.
Hydrangeas are fascinating as they can be manipulated to match your intended
colour psychology better. The primary influencer on bloom colour is the soil pH they’re grown in.
Blue hydrangeas develop in acidic soil. To achieve this, add aluminium sulfate or acidic fertilizers.
Pink blooms appear in alkaline soil. Garden lime can be added to raise soil pH.
Constantly adjust soil gradually – sudden changes can shock the plant. For consistent colour, test your soil pH regularly and amend slowly.
Hydrangeas will show some clear signs when they’re hungry.
Pale leaves or yellowing between the veins could indicate an iron deficiency
Fewer or smaller blooms than usual
Weak or leggy stem growth
Slow or stunted new growth
If your plant shows signs of nutrient deficiency, feeding it is likely a relatively quick and effective fix.
Even with the best intentions, mistakes happen, so it’s essential to keep the results of careless feeding in mind.
Over-fertilising – too much nitrogen encourages leafy growth but reduces flowers
Feeding too late in the year – this can lead to new growth being frost-damaged
Ignoring soil type – hydrangeas thrive in moist, well-drained, fertile soil – feeding alone won’t compensate for poor conditions
Not watering enough – hydrangeas are thirsty plants, and fertiliser without sufficient water can harm rather than help
|
Time of Year |
Fertilizer Type |
Benefits |
|
Early Spring |
Balanced, slow-release feed |
Boosts new growth and root health |
|
Early Summer |
Liquid feed or rose fertilizer |
Sustains blooms and vitality |
|
Late Summer/Autumn |
Compost or mulch |
Protects roots, avoids soft growth |
Early spring, just as new growth appears, followed by a second feed in early summer.
Hydrangea-specific fertilisers are best, but rose fertilisers, slow-release shrub feeds or compost also work well.
Once in spring and once in early summer is usually enough. Container hydrangeas may need feeding every 2–3 weeks during the growing season.
Yes, compost is excellent for hydrangeas. It improves soil quality, provides nutrients and helps with moisture control.
Yes. Soil pH, influenced by feeding choices, determines whether you see blue hydrangeas or pink blooms. It’s worth noting that hydrangeas come in other colours, and not all varieties turn blue or pink.
And remember, follow any specific guidance related to the hydrangea variety that you plant in your garden. We stock a wide range of pre-grown, potted hydrangeas, ready for planting in all sorts of outdoor settings so that you can put your new fertilisation knowledge to good use!
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