How to Plant, Grow, and Care for ‘Empress Wu’ Hosta

When it comes to making a grand first impression, ‘Empress Wu’ knows how to get it done. As the largest commercially grown hosta in the world, this cultivar reaches heights of up to six feet and draws gasps from all who pass. Its giant personality is the stuff of fairy tale gardens and 4-H competitions. 

A shade-lover that grows best in moist soil, ‘Empress Wu’ has the botany of an herbaceous perennial but the body of a shrub. You’ll find it solo as a specimen plant, together with other ‘Empress Wu’ plants in the hosta garden, or mingling with other woodland plants beneath the canopy of a large tree.  

Growing this impressive plant is fairly easy once you get to know its likes and dislikes. Read on for a detailed look at ‘Empress Wu’ hosta’s profile, history, growing requirements, maintenance needs, and problem areas.

Characteristics

‘Empress Wu’ breaks ground in late spring, unfurling slowly into a rounded mass averaging between six and eight feet in diameter. Its foliage is initially blue-green with a waxy coating, but it matures to a soft, dark green as the season progresses. Leaves are deeply veined and fan-shaped with smooth margins and thick, fleshy stems. They can be up to two feet long and wide.

Flower racemes appear in early summer, extending just above the topmost layer of foliage. Blooms are small and tubular in a hue that reads reddish-purple. They grow at short intervals along the axis of a sturdy stalk. Each plant produces several flower sprays, bringing a subtle but welcome burst of color to the shade garden. Blooms are attractive to pollinators, and they are very long-lasting. 

Like most hostas, this plant is hardy in zones 3 to 8 and dies back in fall. It multiplies at a slower pace than smaller hosta varieties but will eventually become crowded and require division. It needs a good deal of space and minimal sun exposure to remain healthy, happy, and attractive. Its root system is relatively shallow, so it grows well in the uneven terrain beneath a mature tree. 

History & Cultivation

The hosta genus includes roughly 70 species and thousands of cultivars that fall under the umbrella of the Asparagaceae family. This hosta is a self-pollinating hybrid derived from hosta ‘Big John.’ It’s named after China’s only female emperor, who served from 624 to 705 AD.  

Native to the woodlands of China, Japan, Korea, and Eastern Russia, hostas experienced instant popularity when Austrian botanist Nicholas Thomas Host introduced it to Europe and America in the mid-1800s. Hosta also goes by the nickname ‘plantain lily’ due to similarities in foliage and flower shape, though it bears no true relation to either plantains or lilies. 

Propagation

This hosta is easy to propagate by seed, stem cutting, and division. If you’re a patient gardener, you can turn one hosta into several in just a few seasons. Since hostas are typically pricey at your local nursery, that’s music to a thrifty gardener’s ears. Here’s a look at the three ways to propagate this giant hosta. 

Seed

Since ‘Empress Wu’ is a hybrid plant that will contain DNA from both parent species, you will not likely get a clone of the big, bold hosta specimen you’re harvesting, but if you want to roll the dice and see what happens, new hostas can be grown easily from seed. Look for gray, cracked pods that appear dry or papery to the touch to indicate that it’s go-time (roughly 30 days after flowering is complete).

Cutting

The easiest way to propagate a hosta identical to the one you already have is through a process known as cutting propagation. It involves snipping off one of the parent plant’s leaves and rooting it in water.

Division

This is typically the preferred method for propagating hosta, but the size of this hosta makes it a little more challenging. The division process involves digging up a whole plant and slicing it into multiple new sections for replanting.

Planting

Once your soil, light, and drainage conditions are met (see below), planting it is relatively straightforward. Since humidity and heat will be at their lowest levels in spring and fall, these are the optimal planting periods. With the right conditions and care, however, a hosta can be planted pretty much any time during the growing season. 

For transplants or nursery-grown specimens, dig a hole that’s twice as wide as the root mass and a few inches less deep. You want the crown to sit slightly above the soil surface to discourage root rot. If you’re planting more than one, allow at least eight feet between holes to account for its mature size. Backfill with excavated soil and tamp down lightly. 

Start seeds indoors at any time or sow directly in the soil when all danger of frost has passed in spring or when freezing temperatures are not expected for six weeks in fall. Plant seeds roughly two inches deep and six inches apart until they sprout, but plan to thin and transplant them when they achieve heights of around three inches. 

How to Grow

The hosta is a shade-loving plant that requires even moisture and good drainage. Once these demands are met, growing this wild, wonderful cultivar is a piece of cake. Let’s look at its light, water, soil, and fertilizer preferences. 

Light 

Like the rest of the hosta genus, ‘Empress Wu’ is a partial shade plant that enjoys a little morning sun and dappled afternoon shade. For best results, choose a location with an eastern exposure, as this will give your hosta a few hours of soft light in the morning. 

Although it tolerates full shade, it will be more vulnerable to threats from disease and insects in locations that have little to no sun at all. Conversely, this cultivar will grow in full sun, but likely not without some unattractive leaf scorch and wilt. 

Water

During its first growing season or after being transplanted, this hosta needs even, regular irrigation. Use a soaker hose or a carefully directed watering wand to direct moisture at the soil rather than the leaf surfaces. Soil should never dry out completely during this initial growth period. Look for wilting leaves to indicate your plant is probably thirsty.

In subsequent seasons, ‘Empress Wu’ will be relatively low maintenance and should get by on moisture from your region’s natural precipitation events. In periods of severe drought or when leaves are showing signs of stress, direct supplemental irrigation at soil and roots once a week or so. 

Soil

Hostas prefer loose and crumbly soil rather than dense and compact, but it usually adapts to less-than-perfect sites. Take a soil test to determine the pH level in the location you’re planning to plant and shoot for a neutral to slightly acidic makeup, ideally somewhere between 6.5 and 7.5. 

If you know you’re going to plant a hosta next season, fall is the best time to amend the soil. If not, spring will do just fine. To improve drainage and achieve ideal consistency, work some compost, humus, or aged manure into the soil. To increase acidity, add a sulfur-based product to the mix. Use a lime-based material to increase alkalinity.

Climate

Hostas are hardy in zones 3 to 8, which means they will die back above ground at the end of each season and return the next year in regions with moderate climates. ‘Empress Wu’ requires a dormancy period of at least six weeks where ground temperatures do not exceed 40 degrees Fahrenheit (4 degrees Celsius), but it can tolerate much longer stretches of cold weather and much cooler temperatures. 

Fertilizing

In normal growing conditions, ‘Empress Wu’ does not need fertilizer and may even structurally weaken if you give it too much. However, if your soil test reveals a nitrogen deficiency or if you feel like your hosta’s leaves are looking a little pale, you can feed it with a product that has an even NPK ratio (10-10-10).

The optimal time for fertilizing a hosta is in early spring when the leaves have just poked through the earth but are not yet unfurled. Then you can feed every four to six weeks with a balanced organic liquid fertilizer.

Maintenance

This is a live and let-live plant for the most part. In optimal conditions, you can ignore it for decades, and it will keep coming back without fuss. But there are a few maintenance tasks you can perform regularly to keep it looking sharp and living large. 

Deadheading

Hosta flowers are a very polarizing topic in gardening circles. Some of us love them and welcome the color in a shady location that is otherwise mostly green. Others see the awkward, messy flower sprays as a nuisance that detracts from the beautiful foliage. 

Whether you’re looking to remove the sprays before they begin flowering or waiting until the mid-summer blooms have faded, the process for deadheading ‘Empress Wu’ is the same. Slide your fingers down the flower stems and use a clean, sharp pruning tool to snip them off as close to the plant’s crown as possible. 

Cutbacks

In late fall or early winter, after the first frost has arrived, hosta leaves will turn yellow or brown and begin to deteriorate. If you can stand looking at them for a while, you’ll be able to grab the leaves near the base and pull them easily from the crown. 

If you’re impatient or prefer a tidier aesthetic, you can lop the leaves off near the crown a little earlier. Be sure their green color has begun to fade, as this signals the end of photosynthesis. Do not cut leaves while they are still bright green, which means your hosta is still absorbing the nutrients it needs for winter dormancy. 

Division

After four or five years, your ‘Empress Wu’ hosta will likely show signs of crowding. Tightly packed, overlapping leaves and a less-than-ideal shape will be the first indications it needs to be divided. You might also notice reduced flowering and diminished foliage color. 

To divide this plant, dig it up completely and slice the root mass into several new sections for replanting. See the propagation section above for detailed instructions on how to perform this important maintenance task while making more of these beautiful plants in the process!

Common Problems

‘Empress Wu’ is pretty low maintenance once established, but it’s vulnerable to leaf damage from mammals, insects, and disease during its first few years. Here’s a look at this cultivar’s most common problems and some solutions for dealing with them.

Rabbits & Deer

Unfortunately, these cute little guys can do a lot of damage in a short amount of time, and they’re highly attracted to a hosta’s large, soft leaves. If you see deer and rabbits hanging around in the yard and you’ve noticed shredded leaf margins, one of these herbivores is the likely culprit. 

To discourage rabbits and deer from destroying your hostas, install chicken wire around your garden or exclude them with a fence that penetrates several inches below soil level. If fencing is not an option, apply a garlic or soy-based deterrent product from your local garden center. Reflective elements and light sensors can also discourage mammals from feeding on your plants. 

Snails & Slugs

Look for chew holes and a slimy black trail on the undersides of your hosta’s leaves to indicate the presence of snails or slugs. Damage from these creepy crawlies will not kill your hosta, but it can be unsightly and frustrating. 

To eliminate snails or slugs, visit the garden at night with a flashlight and pick them off with your hand or spray them off with a hard blast from the hose. You might also have luck with beer traps (a cup of beer buried near the hosta) or slug bait purchased from your local nursery. 

Rot

If your ‘Empress Wu’ is planted in a location that doesn’t drain well, it’s susceptible to root or crown rot. Premature leaf yellowing and leaf collapse that begins near the base are early indications of a rot condition. Mushy, malodorous crown tissue or black, slimy roots are symptoms of advanced disease. You may also notice leaf spots on leaves.

Root and crown rot invite other fungal and viral conditions that are almost always fatal. To prevent the spread of disease to nearby plants, excavate your afflicted plant and surrounding soil. Dispose of the dead plant in the garbage, and don’t plant anything in that area for a season or two. 

Viruses

Tomato ringspot virus, tobacco mosaic virus, and hosta virus X are diseases you should be aware of when you plant hostas. These generally occur when you plant an already infected plant, or they are spread to your hostas from nearby affected plants. Look for mottling in leaf veins, and in the case of ringspot virus, look for target-like discolorations.

Leaf-feeding nematodes and leaf hoppers are also vectors for these diseases. Controlling them is one mode of prevention. Do not plant in areas where foliar nematodes have been present, and do not plant in areas where any of these viruses were present. If you’re unsure which virus you’re dealing with, contact your local extension office. Solarize the soil for at least 8 weeks after removing damaged plants to prevent the spread of these diseases.

Frequently Asked Questions