Hostas are a staple in many shady gardens due to their versatility, variety of sizes and leaf colors, and their ability to thrive in partial sun. With their wide, lush leaves in shades of green, blue, yellow and variegated, it’s no wonder these perennials are so popular. But when it comes to soil pH, are hostas acid loving plants that require more acidic ground to reach their full potential? Or can they tolerate more alkaline pH levels?
Understanding hostas’ preferred soil pH range is key to keeping them healthy and encouraging lush vigorous growth year after year. In this article we’ll take an in-depth look at whether hostas need acidic soil and what pH levels are ideal for these shade-loving perennials.
An Overview of Hostas’ Soil pH Preferences
While hostas grow best in slightly acidic soil they are actually quite pH adaptable overall. Here’s a quick rundown on hostas and soil pH
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The ideal pH range for robust hosta growth is 6.0-7.0, slightly acidic to neutral.
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Hostas tolerate more alkaline soils up to approximately pH 7.5. Growth may slow above this level.
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They may suffer in very acidic soils below pH 5.5. Yellowing between leaf veins can occur.
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For blue hosta varieties, target a pH between 6.0-6.5. Higher pH causes the blue tones to fade.
So hostas grow well in a fairly wide pH range as long as extremes are avoided. Their flexibility makes them suitable for most gardens, even those with more neutral or alkaline soil profiles.
Should I Test My Soil’s pH for Hostas?
Checking your soil’s pH in the proposed hosta planting area is recommended. This will tell you if amendments may be needed to create the ideal slightly acidic conditions.
Here are some tips on soil testing for hostas:
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Take several core samples around the planting area 6-8 inches deep and blend together.
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Home pH test kits provide a quick readout. Follow the kit’s instructions.
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Alternatively, send a sample to your local extension service for lab testing.
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Samples should be taken every 2-3 years to monitor any pH changes over time.
Soil pH varies greatly by region and composition. Testing is the only way to know if adjustments up or down are required before installing hostas.
How to Amend Soil pH for Optimal Hosta Growth
If test results show your soil pH falls outside the target 6.0-7.0 range, amendments can bring it into the ideal zone:
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To lower pH in alkaline soils, work in elemental sulfur several weeks before planting.
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To raise pH in overly acidic soil, incorporate pulverized limestone.
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Recheck pH after 6-8 weeks and reapply if needed.
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Maintain proper pH by fertilizing with an acidic plant food formulated for acid-lovers.
Getting the soil pH in the right zone encourages lush, vibrant hostas. But even if current levels are less than ideal, established plants will tolerate it. Adjusting pH may boost growth and performance.
Are Hostas Acid Loving Enough to Grow Well With Rhododendrons and Azaleas?
While not extremely acidic soil lovers themselves, hostas do combine beautifully with rhododendrons, azaleas, camellias and other plants that require more strongly acidic ground.
Some companion plants that appreciate acidic soil in the 4.5-5.5 pH range like hostas include:
- Rhododendrons & azaleas
- Blueberries
- Camellias
- Japanese maples
- Hydrangeas
- Ferns
- Astilbe
- Heucheras
- Acid-loving conifers
Grouping hostas with these acid-preferring shrubs, trees and perennials creates a lush, cohesive look in partly shaded garden beds.
Signs of Trouble: Preventing Chlorosis in Hostas
If the soil pH creeps too far above neutral into the alkaline range, chlorosis can occur. This refers to yellowing between the leaf veins caused by iron deficiency induced by higher pH levels.
To avoid chlorosis, keep soil pH in the acidic range through testing and amendments. Apply an iron supplement formulated for alkaline soils if yellowing occurs. Ensure adequate moisture since dry soils exacerbate issues.
Severely affected plants may need to be replaced with chlorosis-tolerant varieties like ‘Sum and Substance’.
Ideal Growing Conditions for Hostas Beyond Soil pH
Proper pH is just one factor in growing robust hostas. They also need:
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Organically enriched, moisture-retentive soil. The planting hole should be dug at least a foot deep and wide.
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Cool, partially shaded locations away from hot afternoon sun. Morning sun is tolerated.
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Shelter from strong winds which can shred the large foliage.
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Consistent moisture. Allow soil to partially dry between waterings.
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Slug and snail control measures like diatomaceous earth. Hostas are slug magnets!
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Fertilization in early spring and mid-summer to support growth.
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Division every 3-5 years to rejuvenate mature clumps.
Meeting their site and care requirements keeps hostas looking their very best.
The Takeaway: Hostas Are Quite pH Adaptable Overall
While hostas grow best in slightly acidic soil with a pH around 6.5, they can tolerate a fairly wide pH range outside of extremes. This makes them suitable for almost any partly shaded garden location.
Test soil pH in planting sites and amend as needed to create the ideal slightly acidic conditions. But even if your soil is neutral or alkaline, hostas can still thrive with proper care. Their versatility, variety and lush foliage are tough to beat in shady gardens.
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Hostas prefer a pH between 6.0-7.0 but tolerate 6.0-7.5.
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They combine well with rhododendrons, azaleas and other acid lovers.
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Add lime to raise pH or sulfur to lower it.
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Keep soil moist and monitor for signs of chlorosis.
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Meeting their cultural requirements results in healthy, vigorous plants.
With their wide adaptability, hostas can beautify gardens with a range of soil pH levels. Don’t let concerns over acidity stop you from planting these invaluable shade-tolerant perennials that seldom disappoint.
The Color of a Hosta Leaf
The leaves of a hosta can be blue, green, gold, or even yellow. Someone may have seen a blue hosta. It’s actually a green leaf that has wax on it that makes it look blue. In the summer, when the leaf is out in the sun, it seems like the wax tends to “melt” it.
Leaf color may also be affected by the amount of sun the leaves receive. Hosts can also come in a multi colored variety. These leaves may be a combination of lighter and darker shades of color in the leaf. This type of leaf has a light color in the middle that could be white, gold, yellow, or light green. “Marginally variegated” leaves show a light color on the edge of the leaf.
If you have a problem with slugs, you might want to get a hosta plant with thick, stiff leaves. These hostas are termed “rugose” or are said to have “heavy substance”. These are known to be more tolerant to slug problems.
Propagating your hostas might be the only real maintenance part of hostas that you will need to do. When a hosta plant is six to eight years old, it’s fully grown, and you may have seen that it’s taken over the space you planted it in.
This is a perfect opportunity to split your hosta to allow for continued growth. It’s not hard to make more plants, and you can either replant the other part of the hosta in a different spot in your yard or sell the plant.
If you want to successfully spread your hosta, the most important thing to think about is when you should divide it. The answer is simple, when no shoots are growing from the center of the mature clump.
It might be easiest to divide in the spring, however, summer division is preferred. It should be done at least 30 days before the first fall frost date in August. To make sure to promote better root growth, make sure that there is warm soil and higher humidity.
To learn more, please see Propagating Hostas: When and How to Divide Hostas.
A Brief History of Hostas
Hostas are believed to have originated from eastern Asia from China to Japan and Korea. They are native to forests and prefer growing in light shade. Hosta seeds were sent to France in the late 1700s, and soon after, the first hostas grew in London. Hostas made their way to America the early 1800s.
In 1812, the Austrian botanic, Leopold Trattinnick, grouped all known species into the genus Hosta. He named the group after his fellow countryman, the Austrian botanist and physician, Nicolas Thomas Host.
Today, there are approximately 40 different species although they are all referred to as hostas.
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