Why Hostas Drop Leaves Early in the Season

Hostas are known as one of the most resilient and care-free perennials you can buy. And that's only a few of the reasons hostas continue to be so popular in shady or semi-sunny gardens.

But when hosta leaves die back early in the season, the culprit is almost always lack of water.

To understand why a consistent watering plan is essential for healthy growth in hostas, it’s helpful to know where hostas came from and how they grow.

Hostas were originally from Korea, Japan, and eastern China where they received lots of water, an average of 50" to 60” of rainfall each year, far more rain than in most other areas.

A hosta builds up its energy reserves in the summer and fall and will store that energy in its rhizomes. It will use that energy in the next spring when the hosta emerges.

Inadequate watering during the summer and fall forces the hosta to drop its leaves early. This is how it will protect itself by going into an early dormancy so it can survive periods of extreme dryness.

The result is that in the following year, without that stored energy, that hosta will remain the same size or even get smaller, depending on just how much energy it has stored.

If this inadequate watering happens a few years in a row, while a mature, healthy hosta may be able to tolerate the dry periods by simply going dormant, young hosta roots may actually shrivel and die. Yes, you can kill a hosta!

How Much Water Do They Need?

Generous watering all season long is the best thing you can do for your hostas. A minimum of an inch of water per week, either supplied by Mother Nature or otherwise, is recommended.

Hostas love water! As long as your soil drains well, you basically cannot overwater them.

During the hottest or driest parts of the summer, an increase of water to an inch and a half to two inches is recommended. And it's important to keep this watering schedule until frost.

If you have a large garden, a good soaker hose is definitely worth the investment. I use several like the one pictured above. It's very lightweight, stores easily and I can move it around the garden.

Some hostas are considered "sun tolerant." If you have some of these hostas planted in a sunny area, increase the water to two inches per week. To read our article on sun tolerant hostas, click here.

Hostas that have large leaves will need even more water as those leaves allow for a large amount of transpiration and water loss.

Hostas grown under shallow-rooted trees may require more water as they have to compete with tree roots.

Signs of Short Term Inadequate Watering

Hosta leaves are wilting or drooping. Once watered well, the drooped leaves should perk right up.

Browning Leaf Tips. The browning leaf tips can be cut back.

Fewer leaves are also a symptom of inadequate watering. However, a decrease in leaf size can also mean a nutrient deficiency in which case a balanced fertilizer can help.

How to Water

Deep soakings is much better than frequent light waterings.

Why is that important?

Water applied at a very slow rate to the soil for several minutes encourages deep root growth and limits water wasted through runoff.

Deep soakings also encourage the hosta roots to grow deeper into the ground where they can find water during dry periods.

Conversely, frequent light waterings encourage the roots to grow nearer to the surface where the soil can dry out more quickly.

When to Water

The best time to water hostas is early in the morning when the weather is cooler. This gives the water more time to reach the roots without evaporating.

As a guideline, if the soil around the hosta feels dry to the touch an inch below the soil surface, time for a deep soak.

What can I do?

Watering it well will likely encourage a flush of new leaves to grow.

When you do this, however, keep doing it! You don’t want to encourage new growth and then stop watering letting the plant die back again.

Fertilize Your Hostas in the Spring

Giving your hostas some fertilizer after the Spring frost as passed will give them the boost they need to get growing again.

A balanced fertilizer like the one pictured above will do just fine.

A Treatment with Epsom Salt

The benefits of Epsom Salt on plants are many including that it’s organic, it’s gentle on plants and it’s inexpensive!

To read our article on the benefits of using Epsom Salt on plants, especially hostas, click here.

Improve the Soil

You want soil that easily drains, has water retention qualities and fertility to feed the plant.

A two- to three-inch layer of aged manure, organic mulch like shredded leaves or grass clippings around the plant (but not touching) will help to conserve the moisture in the soil. That mulch layer is also beneficial to hostas by regulating soil temperature and adding nutrients to the soil as the material breaks down.

To read our article on making leaf mold, click here.

To read our article on composting, click here.

To Sum Up

Hostas that are never water stressed will grow bigger, faster and will give you beautiful and healthy leaves longer into the season.

So if your hosta seems to have stopped growing or has actually gotten smaller, stick to a consistent watering plan and watch it come back and give you many more years of beauty in your garden.

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Contributors

Monday, January 13, 2020

Why Hostas Die Back Early in the Season