Last updated on March 15th, 2019
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Hydrangea macrophylla which are also known as bigleaf Hydrangeas, mop head Hydrangeas and also include the lacecap hydrangeas varieties.
There are many cultivars of macrophylla hydrangeas include Hydrangea macrophylla ‘Selma’, Lemon Zest, Penny Mac, Forever Pink to name a few and many many more.
Hydragea macrophylla are well known for there very large flowers and spectacular displays and the ability of the flowers to change colour to pink or blue all though there are some which are white such as Hydrangea ‘Mme Eemile Mouillere’. Depending on the PH of the soil whether it is acidic or alkaline determines the colour of the flower.
Quick Hydrangea macrophylla facts
- There are hundreds of macrophylla varieties
- Flowers tend to be pink or blue and have the ability to change colour depending in the soil PH
- They do not need pruning (just deadhead in after flowering or early Spring
- Size: 3-6ft tall by 5-10ft wide depending on the variety
- Grows well in semi-shade or full sun (sheltered site is best)
- One of the most popular garden shrubs available
- Ideal for beds and boarder
- Some varieties such as Hydrangea ‘Selma’ only grow to 3ft (90cm) and are ideal for containers and pots
- Plants often flower a mixture of blue and pink at the same time
- Hardy shrubs
NEW: Hydrangea macrophylla ‘Endless Summer’
Hydrangea macrophylla ‘Endless Summer’ is a new range of Hydrangeas which unlike most other Hydrangeas flower on both old and new wood which until this new breed was developed with unheard of. This means they produce a spectacular show of flowers and will still flower no matter how you prune them. Like other Hydrangeas, the soil type can still affect the flower colour.
Video on Hydrangea macrophylla
Pruning macrophylla Hydrangeas
Hydrangea macrophylla can be pruned in late Spring after flowering just below the spent flowers to a good strong set of leaves. In less sheltered areas and colder areas, the mop head varieties can benefit from being pruned in early spring as the old spent flowers can provide some protection from frost during winter and early Spring.
Hydrangeas can be pruned back hard if needed to generate new growth and bring old plants back to life. If you do this they will probably not flowers for a few years.
The best place to plant Hydrangea macrophyllas in the garden?
Macrophylla Hydrangeas grow well in semi-shade and full sun, they seem to do best when they get shade in the morning followed by sun in the afternoon. They do grow in shade but will probably not flower very well and may even not flower at all. They will grow in most well-drained but moist soil ideally in a sheltered spot away from cold drying winds.
When to feed Hydrangeas?
Hydrangeas can be feed once or twice a year in summer with a general fertilizer such as fish blood and bone or growmore. Be sure not to use a feed too late in the season (after August) as this can encourage new growth that can be damaged by frost.
Why your Hydrangea macrophylla might not be flowering?
For many people whose Hydrangea looks lush and green with plenty of new growth but no flowers, there are many reasons you might have a problem.
- Soils which are too rich can cause poor flowering as the soil could be too high in Nitrogen.
- Frost damage to young foliage can also affect flowering due to being in areas to exposed.
- Pruning to hard or at the wrong time can also cause a lack of flowers as Hydrangea do flower on old growth.
Changing the colour of the flowers on your Hydrangea macroohylla to pink or blue
Turning Hydrangeas Pink
To help keep Hydrangeas flowers pink the soil needs to be alkaline, if you find your flowers are turning blue you can try applying a dressing of limestone or chalk to the soil around the plant. In very acidic soils this may not work or may need repeating yearly.
Turning Hydrangeas Blue
Blue Hydrangeas need to be grown in acidic soil (high in aluminium) or ericaceous compost in pots. Acidic soil is around PH 4.5-5. A good organic way to try and make your soil more acidic is by mixing Sphagnum moss, composted oak leaves or compost or farm manure into the soil. For Hydrangeas in planters and tubs, you can buy Hydrangea blueing compounds which help turn the compost more acidic and they can be effective.
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