Endless summer hydrangeas is a group of hydrangeas called Hydrangea macrophylla and are also known as bigleaf hydrangeas. These hydrangeas are perennial bushes that have the exceptional ability to bloom repeatedly during spring and summer months.

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They are known to bloom ten to twelve weeks longer than your normal hydrangeas. These hydrangeas grow best in the USDA hardy zones of 4 to 9. Soil pH affects the color of these flowers. They can range from blue in very acidic soil to lilac or pink in alkaline or low acid soils. Endless summer hydrangeas give greater color and aesthetic appeal to your garden for a longer amount of time.

​Pro Tip: To control the color of your flowers add aluminum sulfate to your soil to make a deeper blue or lime to make the flowers pinker.

What You Will Need

As with most flowering plants you can start them directly from seeds or start with an already grown plant. In this section we will let you know everything you will need to start with either one, and give you instructions on the optimal way to plant in both containers and directly into your garden. We will also cover what temperatures work best, where to plant, and how to properly prepare your soil.

Hydrangea seeds/seedlings or plants : You can easily obtain seeds or seedlings from your local nursery. We prefer to start with an already grown plant. This way I can be sure it will bloom, as with seeds they may never sprout and then I will have wasted time I could have spent planting. If you do decide to plant from seed you will need to purchase cell packs or small pots to start them in.

: You can easily obtain seeds or seedlings from your local nursery. We prefer to start with an already grown plant. This way I can be sure it will bloom, as with seeds they may never sprout and then I will have wasted time I could have spent planting. If you do decide to plant from seed you will need to purchase cell packs or small pots to start them in. Spade or shovel

Soil or soil additives : With endless summer hydrangeas you can add lime or aluminum sulfate to change the color of the blooms to your liking. As well, you can add organic matter or fertilizer to beef up less than ideal soil. We suggest a mixture of compost and fertilizer for optimum results.

: With endless summer hydrangeas you can add lime or aluminum sulfate to change the color of the blooms to your liking. As well, you can add organic matter or fertilizer to beef up less than ideal soil. We suggest a mixture of compost and fertilizer for optimum results. Containers , if container planting: If starting seeds in a container we recommend cell packs. If you are planning on keeping the plants in containers for their life span, you will need large pots at least 18 to 20 inches across.

​Step By Step Growing Endless Summer Hydrangeas

​1. Starting From Seeds

To start from seeds, begin with your cell packs and pack them with either nutrient rich potting soil or soil mixed with compost or fertili﻿﻿ze﻿﻿r . Beginning with good soil is essential to the health and vitality of your seedling.

Leave about an inch at the top of the cell pack free of soil. To plant your seeds just dust them over the top layer of soil. Don’t disturb the seeds or try to mix the seeds into the soil. Make sure to keep your seedlings moist at all times, but not soggy.

Pro Tip: If you love your new hydrangeas and would like to plant more next season, collect your seeds directly from your already own plants! It’s best to collect them in fall when the flowers are dying off. Choose a spent flower head and cut it off below the pod. Let the pod dry out, and then remove the seeds. Store the seeds in a cool dry area for planting next spring!

Once your seedling has strong roots and has germinated, it can be moved outside to be transplanted into your garden or a large container. If growing your seedlings in the fall, keep your cell packs indoors at all times. Keep them in a well-lit area and away from intense heat sources.

Once your seedlings are ready to be moved, remove them from your cell pack by lightly squeezing the sides of the cell pack and gently pulling the seedling out by the root ball. Prepare the area you are planting in with nutrient rich potting soil and compost or fertilizer.

When deciding to plant them in the ground, please keep in mind how large these plants can get. Mature endless summer hydrangeas can reach 4 feet tall and have a spread of 3 to 5 feet. Choose a distance from one another that guarantees they will hardly touch when fully grown.

Dig your hole for planting slightly larger than the root ball on your seedling. Make sure that the crown of your plant (where the stems meet the ground) is even with the top soil. Refill your hole with soil and press it tightly around the crown of your hydrangea. Then water thoroughly and slowly.

​2. Starting an Already Grown Plant

You can purchase an already grown endless summer hydrangea from your nearest nursery or places like Home Depot, Lowe’s, or even mail order catalogues. Buying them already grown can save you time and will ensure that you get an already healthy plant to begin with.

Make sure that if you are trying to change the coloring of your hydrangea, you add this mixture to the soil before you plant. Remember to plant with plenty of room between the plants so that they don’t crowd one another. When planting an already grown hydrangea, it is absolutely necessary to fertilize and prepare your soil well, as you don’t know how healthy the soil is that they’ve been grown in.

Take your hydrangea out of the pot it was bought in using the same technique we taught you with the cell packs. If the roots are tightly wound, gently loosen them with your hands or fingers before planting. This will encourage your plant to spread and stimulate root growth. Place the plant in your hole and refill to the crown of the plant. Compress the soil firmly around the plant and water thoroughly.

When planting your endless summer hydrangeas, whether from seed, seedling, or already grown bush; there are a few things to take into consideration. Take note of your hardiness zone. In zones 4 thru 5a your hydrangeas will crave and be able to thrive in full sun.

The further south you live, or in hotter hardiness zones we recommend planting in an area that receives early morning sun with dappled shade in the evening. In southern areas, hydrangeas are less tolerant to intense sun. Your endless summer hydrangeas should bloom all spring and summer long.

​3. Watering

When watering your endless summer hydrangeas, you will first need to know your soil type. Hydrangeas prefer well-drained, damp soil, but not soggy.

Overwatering your hydrangeas can cause them to stop producing blooms. Clay soils retain more water and will need to be watered less. Sandy soil holds less water and will, therefore, need to be watered more. Watering your hydrangeas in the morning or even when the heat is less intense is best.

Pro Tip: Applying mulch around the base of your plants will help conserve water in them and will lengthen times between watering.

Outdoors Hydrangeas soak up water very rapidly. Endless summer hydrangeas grown out of doors do not need as much attention to watering as container plants do. Water thoroughly in the morning or afternoon, and check throughout the day to make sure they are moist but not soggy. Avoid getting the sepal (flower ball) wet as this can rapidly lead to gray mold. We suggest a soaker hose, such as this one, for your watering in hot, summer months:

Container Watering Watering endless summer hydrangeas in a pot or container can be a bit trickier than watering them in a garden bed. When watering a container planted hydrangea fill the pot to the top rim, then let the water drain fully thru the bottom. Repeat this process until the soil is moist but not soggy. It is important to water this way to make sure that even the roots are being watered deeply. Potted hydrangeas require more water than even their garden grown counterparts, so be sure to check thru the day to make sure the soil doesn’t become too dry.

​How To Care

​1. Pruning

Endless summer hydrangeas generally require less pruning than most varieties of hydrangea. These hydrangeas bloom upon the old growth from the previous and current years, which leaves little for you to do. If you feel the need to prune them , only prune them to shape them or for fresh cut flowers. Beware of pruning too much, it will cause you to have less blooms next year.

2. Diseases

Endless summer hydrangeas are only affected by a few, non-serious diseases, such as bud blight, leaf spot, and powdery mildew. To cut down your chances for powdery mildew, make sure not to plant in too much shade and try not to water in high winds. This disease will deform new growth and cause foliage to fall off prematurely. Pruning and disposing of infected foliage and clearing away older, fallen foliage will also discourage powdery mildew.

Bud blight attacks old or wounded areas of the hydrangeas and manifests as red or brown patches on leaves. Thin the upper canopy of the hydrangea to allow for better airflow and destroy any diseased part of the plant as soon as you notice it.

Leaf spot is caused by wet, warm weather. Angular, small, water soaked leaf patches deepening into a brown or purplish color will indicate infection. To prevent the spread of this infection, avoid splashing the foliage as you water it. Prune away diseased leaves and destroy fallen ones.

3. Overwintering

If you live in a location that develops freezing temperatures in winter months, you will need to protect your endless summer hydrangeas during this time.

Endless summer hydrangeas bloom upon last year’s growth as well as the current year’s growth, so it is best to protect the flowering buds on the “old wood” (last year’s growth).

The optimal way to do this is to make sure NOT to cut back these plants after August 1st. Leaving fall buds and flowers over freezing months provides winter interest, and guarantees that you aren’t cutting back buds that will later become flowers.

Mulch, leaves, and straw are great options for insulation for your hydrangeas. Pile one of these options around the base of your plants at least twelve inches high to protect roots. When spring returns wait until all danger of frost has passed before removing your insulator.

Container planted hydrangeas will not need as much mulch but will need to be watered lightly, as they will not be receiving moisture thru the weather.

​Conclusion

We truly hope you have enjoyed this informative article. We hope that we have answered all of your questions or concerns about your endless summer hydrangeas. We covered everything from growing seedlings to how to water and back again.

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