Blue Hostas: How To Plant, Grow, and Care For These Popular Perennials
Thinking of planting some Blue Hostas in your garden, or in your yard? There's some very specific information you'll need if you want to make your plants stick around successfully. In this comprehensive guide, Gardening expert Madison Moulton covers how your can successfully plant and care for Blue Hosta plants.
Gardens are filled with a wide range of vibrant, enchanting colors that almost look too good to be true. Unfortunately, one color is largely missing from that range, and the natural world in general – blue. As one of the rarest plant colors to come across, it is no wonder why one of the most striking blue plants out there, the blue hosta, is so popular.
The Hosta genus is filled with incredible diversity in color, texture, and size. These long-lasting plants tolerate a range of conditions and climates, often outliving the other plants in your garden. Blue hosta varieties are no exception, providing a range of blue and silvery hues in sizes great and small.
If you’re looking to complete your garden kaleidoscope, or simply want a hardy perennial to fill up a shady spot, you won’t go wrong by planting a blue hosta.
Blue Hosta Plant Overview
Plant Type Herbaceous Perennial
Plant Family ASPARAGACEAE
Plant Genus Hostas
Exposure Dappled/Full Shade
Plant Spacing Variety Dependent
Watering Needs Moderate
Plant Height 6 inches to 3 feet
Maturity Rate 4-5 Years
Planting Depth Variety Dependent
Pests Deer, Slugs, Snails
Companion Plants Ferns, Heucheras
Soil Type Rich, Well-Draining
Hardiness Zone USDA 3-9
Growth Rate Slow
Plant Height 6 Inches to 3 Feet
Plant Maintenance Low
Don’t Plant With Full-Sun-Plants
Diseases Anthracnose, Rot
Where Do Blue Hostas Come From?
Scientists believe these popular plants originated in China, where they can still be found growing wild today. Hosta plantaginea spread throughout the East of China, reaching Korea, Japan, and Russia, where they are now considered native.
Hostas had particular success in Japan. Landscapers throughout history created new cultivars and often planted the varieties in traditional Japanese gardens. Today, most garden hosta varieties can be traced back to wild Japanese landscapes.
From Japan, hostas were introduced to Europe by Philipp Franz von Siebold. A doctor and botanist, Siebold studied Japanese flora and fauna in the early 19th century. Expelled from Japan in 1829 for possessing maps of the territory, he brought over 10 000 specimens back to Leiden in the Netherlands.
Hostas spread to other parts of Europe and to the Americas soon after, directly from Siebold’s collection or from Japan itself as more botanists took interest in the plant. Studies of the 19th-century plant taxonomy indicate that the plants reached North America as soon as the 1830s, beginning their continued reign as one of the most popular garden plants.
While Siebold can be credited with transporting these plants across the world, he did not give them their catchy name. That is thanks to Leopold Trattinnick, an Austrian botanist, who named the genus after fellow botanist Nicholas Thomas Host. An alternative name, Funkia, was used by Siebold to identify the plant and is occasionally used as a common name for the genus.
The identified cultivars started small in number, containing only a few blue varieties. Today, there are thousands of cultivars, many of which sport the blue hue gardeners are after.
Hostas are commonly propagated by division. This method is considered the simplest and most reliable for home gardeners. However, it is not a quick method. As these plants grow relatively slowly, you will only be able to divide your hosta regularly every few years. These plants can also be propagated from seed or leaf cutting, with a lesser chance of success.
The best time to divide hostas is in spring or early summer, taking advantage of the growing season to give divided plants a much-needed boost. Your plants will tell you they are ready when new buds begin to emerge, a sign of rising temperatures.
They can also be divided in fall, well before the first frost hits. Cold soil will prevent the tender roots from establishing, so give the plants at least a month or two to settle before winter sets in.
To divide, dig up the existing plants and gently shake the soil off the roots. For smaller plants, you may be able to pull the root clump apart, but larger plants will require a cut with a sharp, clean knife. Identify the buds and cut the plant into sections containing at least two or three buds and a healthy number of roots.
Take this opportunity to remove any dead or damaged parts of the plant to provide your divisions with the best start.
Once divided, simply replant these new sections back into the garden. Hostas are not fussy when it comes to handling and most will grow happily once divided. It’s no excuse to mistreat the roots, but don’t stress if you break off or snip a root or two accidentally. Your beloved plants are bound to bounce back.
Due to the many cultivars and hybridizations, hostas propagated from seed will likely look nothing like the plant you got the seed from. It may lose its color or variegation – not something you want to face if you’re looking to keep your this plant looking blue.
The success of the plant is also not guaranteed. It may not grow as well as the original plant, or may not sprout at all, making your seed planting efforts futile.
If you’re looking to take on the challenge despite these downsides, harvest the seeds when the seed pod has dried out and changed color. Sow within a year as you would other perennials in your garden. Sprouts will appear within two weeks, and the seedlings can be transplanted after several leaves have formed (in around two months).
Propagation by leaf cutting is possible, but very unlikely to yield strong, healthy plants. Gardeners attempting to root cuttings either in soil or in water often report a success rate of below 50%. You may attempt this method by removing a leaf with some root tissue attached. But don’t invest too much time – you may end up disappointed.
This plant can technically be planted any time of the year. However, to give them a good start, spring and autumn are preferred. This avoids any potential damage from high summer heat or frosty winters. When planting in the fall, get started early in the season to allow the plants to establish before the soil cools and hardens. Regions with cooler climates can also plant in early or late summer, avoiding the peak scorching temperatures.
How much space you leave between each plant will depend on the variety. These plants can vary greatly in size, so it’s best to check the label to get an idea of their mature size. Keep in mind that many blue hosta varieties take several years to mature. Don’t plant them too close, or they will compete for space and resources as they continue to grow. Hostas can be companion planted with other hostas, or other plants.
When preparing the planting site, ensure the soil is loose and enriched with organic matter. Dig a hole close to the same depth as the pot, but with greater width. This encourages the roots to spread outwards to anchor the plant rather than downwards, as hostas are relatively shallow-rooted for their size. Once planted, cover with a thick layer of mulch to seal in moisture and prevent weeds.
Blue Hosta Care
Blue hostas are not only favored for their color. These plants are also incredibly easy to care for when given the right conditions. Left to their own devices, they will thrive without much fuss or maintenance, and even have the potential to outlive their owners.
Plants of the hosta genus typically prefer dappled shade throughout the day. This makes them ideal for tricky spots under trees. They can also thrive in positions that receive some cool morning or afternoon sun.
However, when it comes to blue hostas, it’s best to err on the side of shade. Exposure to too much sunlight can cause the blue leaves to appear washed out, losing their attractive color. Leave them in this position for too long, and they may lose their color altogether, turning the leaves green for the rest of the season.
If you lack the ideal spot with dappled shade, many varieties can also survive in full shade. They may not grow as quickly without the extra boost of energy, but will be much happier there than in a sunny spot.
Blue hostas prefer soil that is consistently moist, but not waterlogged. This is a fine line to tread, but it is far better to underwater and leave the soil slightly drier than to leave the roots sitting in soggy soil, encouraging disease and root rot. Preventing overwatering is especially important for plants in deep shade, as the water will evaporate far slower than the sunnier parts of your garden.
Soon after planting, water around twice a week, taking rain into account. Once established, a deep watering once a week should be sufficient. In warmer weather, increase your watering schedule to keep the leaves happy and the roots cool.
Equally as important as when you water is how you water. Overhead watering or excessive rainfall can cause the blue coating on the leaves to wash off or become spotty. This coating emerges with the new leaves every season. In other words, once it is washed off, the plant will lose its blue color for the rest of the season. Always water the soil directly or install drip irrigation to keep the leaves free of moisture.
Not particularly fussy about soil, this plant can tolerate a range of conditions. As long as the soil is consistently moist and well-draining, they won’t complain.
For the technical gardeners that want to give their hostas the best start, ensure the soil has a slightly acidic pH just below 7, and enrich with plenty of organic matter for aeration and water retention.
Barring extremely cold or extremely hot climates, these plants should be happy just about anywhere. These plants are incredibly cold-hardy, withstanding winter temperatures well below 40F. This is because the leaves die back in winter during the plants’ dormant period, emerging again when the weather warms. In fact, all hostas need colder weather over winter to trigger this dormancy, allowing new leaves to grow the following season.
This also means they are less tolerant of extremely warm climates. In general, these plants do not handle heat well, but some varieties are more tolerant of warmer temperatures than others. Ensure whichever variety you choose to plant is suitable for the climate of your region.
When planted in good quality soil enriched with compost, blue hostas will need little to no fertilizing, adding to their easy-going nature. If the plant appears to be struggling, you can apply more organic matter throughout the season to slowly break down into the soil. This should be enough of a boost to perk up your plants.
If your soil is lacking nutrients, you may want to use a slow-release fertilizer in spring to take advantage of the peak growing period. Alternatively, you can apply a balanced liquid fertilizer once a month throughout spring. This will give your plants enough nutrients to last the rest of the year.
No matter which options you choose, hostas should only be fertilized in spring. Fertilizing in late summer encourages new growth that is likely to die off when frost approaches. Fertilizing in autumn is also not advised as it promotes growth when the plant is headed towards dormancy.
When using a liquid fertilizer, ensure it is focused on the soil around the roots and does not touch the leaves of the plant. Any splashes of fertilizer that reach the leaves will cause that spot to burn. Water immediately after using any granular fertilizers to distribute the nutrients to the roots.
Blue hostas require very little maintenance and prefer to be left alone for most of the growing season. To save water while keeping the soil moist, regular mulching is the only recurring task, but is not absolutely necessary for the plants’ survival.
You can choose to cut back the leaves just before winter as they begin to die off. This prevents potential problems with diseases and keeps the plant tidy. However, like mulching, this is not a necessity. They should do just fine without this extra trim.
Blue Hosta Varieties
Gardeners are spoiled for choice when it comes to blue hosta varieties. Whether you’re looking for one of the famous large-leaved varieties, or need a compact container hosta, there is an option for you.
Hosta ‘Big Daddy’ and ‘Blue Angel’ are massive both in size and in popularity. ‘Blue Mammoth’ and ‘Blue Umbrellas’ are not far behind as evidenced by their cultivar names. ‘Blue Hawaii’ also sports large leaves, but is most known for its deep blue color – one of the bluest hostas you can buy. These varieties all feature dainty white or lavender flowers in summer that contrast well with the impressive leaves.
‘Halcyon’ is one of the most popular medium varieties. Its shorter stature and stunning blue leaves have been used in the production of many sports, including ‘Carolina Blue’. Similar to ‘Halcyon’ but with a slightly different leaf shape is the impressive ‘Abiqua Drinking Gourd’, loved for its cupped silvery-blue leaves. Those looking for a variegated medium variety will appreciate ‘Blue Ivory’, featuring blue-green leaves edged in cream.
Some common small varieties are easily identified by the inclusion of ‘mouse’ in the cultivar name. Standing out amongst the smaller crowd is ‘Blue Mouse Ears’, followed by its cousin ‘Snow Mouse’. ‘Blue Elf’ and ‘Blue Moon’ also feature prominently. These compact options are perfect for small gardens or growing in containers.
Pests And Diseases
The carefree nature of these plants extends to the realm of pests and diseases. With the right care, few gardeners come across these issues. But, there are some potential problems to manage to keep your blue hosta completely pest and disease-free.
The most common fungal disease affecting hostas is Anthracnose. This disease thrives in warm, wet conditions, causing discolored spots and damaged edges on the leaves.
While it may not kill the plant completely, quick response is vital to ensure it does not spread to other leaves, or worse, other plants in your garden. Avoid overhead watering, keep the soil cool in warm weather with a layer of mulch, and remove any affected leaves as soon as you spot them.
If you let your blue hostas sit in water, they will be vulnerable to a common soil-borne disease: crown rot. This can cause the Hosta’s leaves to turn yellow, turn brown, curl, and the roots to rot, ultimately killing the plant. The best defense against crown rot is good watering practices – never overwater your plants and ensure they are planted in well-draining soil.
Other less common diseases to be on the lookout for include petiole rot, nematodes, bacterial soft rot, and Hosta Virus X.
If you discover small holes in your leaves, you are likely battling a slug or snail infestation. The annoyance of many a gardener, these pests love the damp, cold conditions of blue hostas. They tend to hide amongst the leaves during the day and start munching at night, making them incredibly difficult to spot.
To catch slugs and snails, install a beer trap near your hostas. To create the trap, place a deep dish or bucket filled with beer in a hole in the garden. The smell will attract all the slugs in the area, causing them to fall into the bucket and away from your precious plants.
While snails and slugs find hostas relatively tasty, deer consider this plant their favorite garden snack. If you wake up one morning to find your previously lush leaves stripped down to the stem, a deer is the likely culprit. There are many safe methods for keeping deer out of your garden, from high fences to motion-activated gadgets that scare them away.
Rabbits may also be a concern, but don’t completely destroy the plants as deer do. They tend to prefer eating newer, tender foliage though, so it’s important to keep them out of the garden.
Blue Hosta Uses
Blue hostas serve many purposes in the garden, from design to filling that tricky spot where no other plant will grow. They are great foliage plants for shady spots, emulating the look of a tropical garden in non-tropical climates. They are suitable for growth under trees, or even indoors if the right variety is chosen. But most of all, they are appreciated for their stunning blue color, which is difficult to find in any other plant group.
Many gardeners prizing these plants for their ornamental value may not realize they are completely edible too. Common in Japanese cuisine, the leaves are often fried or boiled similar to spinach. This plant has a taste similar to asparagus (understandably, as hostas are part of the asparagus family).
Harvest leaves when they are still young, as the more they mature, the more bitter they become. If the leaves aren’t to your liking, use the milder flowers as an edible garnish in salads.
Why Are Blue Hostas Blue?
Despite their convincing appearance, blue hosta leaves are not actually blue – they’re green. The blue tint comes from a glaucous coating (a waxy blue-grey substance) that covers the leaves and protects them. This is why the shade or intensity of the blue may change as the plant grows, or throughout the season with changes in the weather.
Why Did My Blue Hosta Turn Green?
Blue hostas may turn green when they lose their waxy coating that provides the blue sheen. This could be the result of a number of factors – excessive rain or overhead watering, high heat or humidity, or overexposure to sunlight. This coating can even be rubbed off with your fingers while touching the leaves. Once the coating is removed, the leaves will remain green until the leaves die back and reemerge next season.
How Can I Keep Them Blue?
Good care practices will help your hostas retain their beloved blue color. Always water the soil directly – don’t water overhead – and consider protecting the leaves from prolonged periods of rainfall by planting under trees or other natural covers. Keep the plant out of the midday sun and protect it from extreme heat in the height of summer if temperatures soar.
What Is The Largest Blue Hosta Variety?
You cannot go wrong with Hosta ‘Blue Angel’. The wide, textured leaves are impressively large, layered over each other to form a stunning statement plant. This variety is known to reach heights of over 35 inches and can spread 4 feet wide when mature.
Can I Grow Them In Pots?
Absolutely. Blue hostas are excellent container plants, filling up space well and cascading down the sides of the pot. Due to their size, popular large varieties should not be grown in pots, but smaller varieties like ‘Blue Mouse Ears’ will thrive. Keep in mind that the water in containers drain and evaporates faster than out in the garden, so you may need to water it more often.
Blue hostas are a carefree perennial guaranteed to look spectacular in any garden. Their glossy blue foliage is second to none, made even more impressive by the imposing size of larger varieties. Whether you choose one, or collect them all, you can’t go wrong adding one of these popular perrenials to your backyard.