Summer Crush Hydrangeas are a bigleaf/mophead type of hydrangea that doesn’t grow very tall but produces huge beautiful flowers. Summer Crush Hydrangeas benefit from fertilizer, as do most hydrangeas, but the type of fertilizer you should use does vary based on what you need. I looked into the ideal fertilizer for Summer Crush Hydrangeas and here’s a summary.
Use an acidifying all-purpose fertilizer (10-10-10) to produce blue flowers, and use an all-purpose fertilizer (10-10-10) and add some lime to produce deep pink flowers. An acidifying fertilizer will usually have the format 10-10-10-(X), where X will be the ratio of sulfur that acidifies the soil.
In this article, I will explain exactly how and when to apply fertilizer to Summer Crush Hydrangeas. There is also a different fertilizer you should use if your plant is not producing many flowers or isn’t blooming.
Read on as I tell you everything you need to know about fertilizing this amazing variety whether you’re new to gardening or are an experienced green thumb.
How To Apply Fertilizer for Summer Crush Hydrangeas
You should fertilize your Summer Crush Hydrangeas once in early spring and again 3 months later in early summer. This is the time of year when your Summer Crush Hydrangeas are putting on new growth and blooming.
After this time they drop all their leaves, and the flowers turn dry crispy and lose all their petals. Summer Crush Hydrangeas as with all big leaf hydrangeas go dormant in the autumn and winter.
The main purpose of fertilizer is to help them to grow faster. But, because they’re dormant in late autumn and winter they won’t utilize the fertilizer.
The amount to give them is 1 pound (2 cups) per 100 square feet. I’ve converted these numbers to make it easy to figure out based on how many Summer Crush hydrangeas you’re fertilizing. Since it’s quite common to grow them in groups or in a row:
| Number of Summer Crush hydrangea plants | Amount of 10-10-10 fertilizer | Number of applications per 6lb (2.7kg) bag |
| 1 | ⅔ of a cup | 18 applications per bag |
| 2 | 1 ⅓ of a cup | 9 applications per bag |
| 3 | 2 cups | 6 applications per bag |
| 4 | 2 ⅔ cups | 4.5 applications per bag |
| 5 | 3 ⅓ cups | 3.6 applications per bag |
The general rule is to apply about ⅔ of a cup per plant. Typically fertilizer comes in 6 lb (2.7 kg), or 40 lb bags. A 6 lb bag will give you 12 cups of fertilizer or enough for 1 plant for 12 seasons or more seasons.
Each fertilizer brand can differ, so it’s always best to double-check the directions on the packaging. The main thing is to never apply more than two applications of the recommended amount of fertilizer per year.
There are two main types of fertilizers slow release and quick release. A slow-release fertilizer can technically be applied at any time because they release the nutrients into the soil over 1 to 2 years.
These slow-release fertilizers are ideal if you don’t want to apply fertilizer as often. But, this slow-release feature comes at a price premium. And applying fertilizer generally isn’t too big of a chore and is quite enjoyable.
Type of fertilizer to use if it’s not producing blooms or only a few
If your Summer Crush Hydrangeas aren’t producing blooms or it’s not producing many blooms at all you want to use a triple phosphate fertilizer. The reason is that phosphate increases bloom production.
When you see the rations on a pack of fertilizer such as (10-10-10) is means equal parts N, P, K. Or, Nitrogen, Phosphorous, and Potassium. Here’s a table that shows what each letter in the naming of fertilizers means, and how it helps plants:
| Nutrient | Helps with |
| N – Nitrogen | Promotes growth of the foliage, everything above the ground |
| P – Phosphorous | Promotes growth of the roots, everything below the ground. Also, helps with flower production |
| K – Potassium | Helps all aspects of the plant |
| Sulfur | Acidifies the soil, turns the flowers blue |
| Lime | Alkalizes the soil, turns the flowers pink |
When you’re not getting good flower production giving them more phosphorous in the form of a triple phosphorous fertilizer gives the flowers a significant boost. The other reason it’s not producing many flowers is if there was a frost in the winter.
A frost can kill the buds that have formed on old wood. Therefore, only the new wood – this season’s growth – will have flowers. A good option if you live in a climate that is susceptible to frost is to grow Summer Crush Hydrangeas in pots.