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All You Need To Know About HOSTAS
Hostas make an outstanding ground cover, are excellent border or a living edging for a walk, or may be used as accent plants in almost any garden setting. Particularly useful in the shady parts of the perennial garden, Hosta are mostly grown for their attractive foliage - adding interest, texture and color, and just after the middle of Summer, they begin to provide the additional luxury of lovely and sometimes highly fragrant blossoms. Most prefer at least half shade (that does not mean a half day of full shade and the other half bright, uninterrupted, brutally hot afternoon sun!), but some can handle a little more sunshine while others will tolerate almost full shade. Precious few can handle full sun...and look good. A close friend commented recently that "Hosta will grow on the top of a bald man's head!" In fact, this same friend says he has several growing in full sun! Well...I've never actually seen the hosta he says he grows in full sun, so it remains unsubstantiated...and, I might add: doubtful. Yes...all will "grow" in full, all day, uninterrupted sun...but what will they look like under those harsh, stressful, and undesirable conditions? Take a look!
Hosta, on average, reach about 10 to 14 inches tall. (We have some true miniatures in our gardens which rarely reach beyond 3 or 4 inches tall...others may achieve a foliage height of nearly 3 feet!) Leaf shapes vary between lance and large, round oval. Texture for the most part is glossy or semi-glossy, though some sport a soft, velvet surface that is almost irresistible to touch...while more than a few have deeply-puckered or quilted leaves.
Some Hosta have rather striking, contrasting patterns of color while others are basically unadorned with variations. Most such unvariegated foliage is the common - but none the less, attractive - green, blue-green, golden yellow or blue (yes, blue). Many of these leaf types make excellent background color, or a suitable foundation or accent in cut flower arrangements.
Hosta blossoms appear along graceful, fairly strong stems - some very tall; others barely reaching above the foliage - that emerge from leaf clusters between late July and mid-September ('Royal Standard', one of the most fragrant, tall white ones, blooms so late that the last few flowers are almost always nipped by frost in the Fall). Colors are white, pale lavender, lavender, almost blue and violet. Flowers are generally bell- or trumpet-shape and open from the bottom up, similar to campanulas or foxgloves. They last quite well in the vase, and some Hosta flowers are occasionally utilized in bridal bouquets and tiaras.
Culture and Propagation
Hosta can be grown from seed but you will doubtless prefer the safer and more effective method of crown division. Early in the Spring, dig the entire clump, shake or wash all old soil from the oftentimes enormous root system, and either pry or cut the crown apart into 2- or 3-"eye" divisions. As always, use a clean, sharp knife, being careful to avoid getting your fingers in the way. It's an especially good idea to wash the blade between clumps to preempt the possibility of spreading soil diseases from one part of your garden to another - or to a friend's yard.\
Rebuild the soil, adding some sand and generous helpings of compost or other suitable humus (Hosta like it rich, deep and somewhat moist). Now would be a good time to adjust soil pH (Hosta like it neutral-to-sweet...so don't be bashful with the lime or wood ashes). Just before replanting, add a little 10-10-10 or organic equivalent, and some extra steamed, deodorized bone meal in the bottom of the new planting hole.
While dividing and replanting, avoid allowing roots to dry out so as not to shock them too badly, and be sure to spread the roots out well - they don't care to have their ample 'feet' crammed into a tight little hole. Water them thoroughly, protect from direct sun for a frew days, and keep them moist for the remainder of the season.
Once established, a Hosta can remain in its location for several years. Consider division and soil rebuilding when crowding occurs or when the plants have slowed their annual rate of growth or when foliage shows early signs of stress or malnutrition. If, after dividing, you end up with more plants than you have space for, consider sharing your bounty with a friend or neighbor. Just be certain that those which you share are clean, healthy and, if possible, correctly labeled.
Very Few Problems
Hosta have precious few enemies - indeed, they might even be called the "perfect" perennial for shade - but those that are a problem can be very serious, indeed. Slugs love Hosta foliage, and if you have them around, you'll need to keep a close watch for telltale signs - and deal with them promptly.
Here's the sum total of our efforts to control slugs or to deter them from becoming a problem in the first place: adjust soil pH (acidity/alkalinity) to at least 7.0 (neutral) or slightly higher. Here's something that'll come as a surprise to all the Hosta world's 'beer-in-the-saucer' and slug-pellets aficionados: SLUGS PREFER ACIDIC CONDITIONS - that's why - in Nature - you'll find most of the slimy critters back in the dark, moist cool, humusy, acidic woods and weeds. Gardens with serious or even severe slug problems are invariable maintained in a far-too-acidic condition - odd, since most perennials grown in those very same gardens prefer conditions only slightly-acid to near-neutral!
Slugs will studiously avoid gardens in which the soil is treated with appropriate amounts of lime or sweetening wood ash; their physiology is powerfully acidic....alkaline conditions are abhorrent to them! They'd much prefer to remain in the acidy woods and weeds. A mulch of freshly made compost will also help to deter slugs (because the pH of properly-made compost is near-neutral!). Use commercial slug pellets only in extreme conditions - and then with great care and concern for children, pets and wildlife. One last slug-point: forget the saucers of beer and crawling around during the dawn and dusk with flashlights, salt shakers and scissors. Keeping it simple has, for our once-heavily-slug-infested acidic woods, been the only way to go. Chances are better than good that it'll work for you, too.
Aphids can be another annoying threat and, if allowed, can seriously damage flowers. Control minor infestations of aphids with any of the readily available natural controls. I prefer pyrethrum (the refined extract of common painted daisies. I've also found that a thorough cleansing shower with a nozzeled garden hose usually does the trick quite well...without pesticides.
Occasionally, two-spotted red spider mites decide to set up housekeeping on hosta, particularly near the tip of flower stems. A neat, properly-maintained and monitored garden environment generally discourages mites. A blast from a hose usually knocks them for a terminal loop.
Deer, on the other hand, can be a serious problem, defying nearly all cures - natural, chemical or mechanical. We've tried dog, coyote and human urine, little bars of odiferous soap, 5-1/2 foot tall HOT electric fences, flash tape, you name it...and, after just a few nights of contemplation, trial and error, most of the initial huge herd of rampaging deer almost magically - and annoyingly - adapted. We've finally landed on a double (spaced about 36" apart), but much shorter, electric fence surrounding the entire nursery. So far, so good. We put a 30-mile "brush-burner" on a little over a half-mile of wire. Needless to say, we never even accidentally touch it!
Other Fur-Bearing Critters
Mice and voles can also be a problem, but at least they're a manageable one. Our cat, combined with numerous traps and constant vigilance, keep the damage to a minimum. Rodents seem to concentrate on worms, bugs and grubs, and generally stay away from vegetarian cuisine, at least in our garden. (Because we find it unnecessary to slather deadly poisons all over the gardens, we entertain a lot of worms and beneficial insect larvae - with plenty of extras to keep a few fuzzy little rodents happy.
So.....if you have a spot in your garden that gets half or more shade, has fairly deep, rich soil and at least a modicum of available moisture but can't decide what to plant there, check out the varieties available, and consider adding the color, texture and flowers of Hosta to your perennial spread.
Virtually every week during the growing season at least 2 or 3 "gardeners" confront me with the implied accusation that I clearly don't know what I'm talking about when it comes to hosta care and culture. It nearly makes me crazy when the seemingly endless stream of self-proclaimed world's greatest hosta experts puff themselves up with that "I've got you!" look on their faces, lean in and look me straight in the eye and proclaim: "Well, I've got them planted right out in the sun...and they grow just fine!" So I explain (usually patiently) that yes, they'll "grow" in uninterrupted, all-day, hot sun...but that's not what they prefer. They'll look and perform much better if given a fair amount of shade...especially during the hot, bright, afternoon. I'll tell them that one with solid green leaves (like the magnificent H 'Royal Standard' with late-season, blistering-white and wonderfully-fragrant flowers) will stand a much better chance of surviving in a sunny, southwest-facing exposure... but even that one won't like it. (Sometimes I simply walk away. I've got much more pressing things to do than stand and argue with a totally inflexible know-it-all!)
Thank goodness (!) many of them listen and say something like "I didn't know that...I guess I won't buy this one with the lighter colored [or delicate variegated] leaves....Thanks for your help."
Sadly, however, some others totally ignore the recommendations...and buy what they want. They're not gonna let some 70-year-old crank with dirty knees, cracked cuticles, and compost-stained fingernails who thinks he knows more than they do tell them what or what not to plant! No suh!
So....I took a ride around the neighborhood the other day (Sept 7, 2005...long before even a hint of frost). Brought along a camera. Practically every street had at least one very revealing demonstration of how not to grow hostas. Here are some examples of what most will look like when they're plunked out in the sun (click the picture for an enlarged view...return with the "Back" button) —
Let me ask again: Will hostas grow in full sun?
Sure! But if you want them to be attractive and earn the praise of fellow gardeners, with clear unblemished leaves, and nearly breathtaking flowers that last and last... follow the advice of the real experts: hostas like it shady, moist, with extra organic matter in the soil, and twice-annual feeding with something other than some magic blue water! Anything less, and you might just as well forget about hostas....and sprinkle some grass seed.
"What's making holes in my hosta leaves?"
Listen to this recent question from a Minnesota visitor to our web site: "What can you do when you have little holes in your hosta leaves? And also what eats the whole root and kills the plants?"
Actually, this is one of the most frequently-asked questions I hear, so I thought our readers and visitors might like to share in my response.
Holes in hosta leaves are most often produced by slugs, grasshoppers and certain caterpillar-like insects. Some types of leaf-cutter bees also take almost perfectly-round sections right out of the middle of leaves. Considering you're in Minnesota (climate and conditions not unlike ours), I'd guess yours are the result of slug or grasshopper feeding - the most common cause.
More than a few gardeners these days are leaning away from highly-toxic bug sprays - which I think is a wise course of action - and selecting equally-effective natural materials. Slug pellets are attractive to birds, small animals, household pets and small children (even cats who've lain on, or walked through, pellets later ingest poisons during their grooming process). Residues get into the soil, then into our food chain and water supplies. I don't use them...the potential consequences are too disturbing.
Slugs are physiologically acidic - powerfully acidic - and are repulsed by alkaline conditions. Oddly enough, hosta grow and perform at their maximum in alkaline soil...........so...........if the soil pH is adjusted (sweetened) to the point where hosta (and almost all other perennials as well) like it, the slugs will avoid that area. Read this article: Slugs & Snails and look in Archives for other articles).
Mice, shrews, moles, voles and gophers consider hosta crowns (roots) a particularly tasty treat, and will munch on them during any time of the year - but especially over winter, under the snow when other foods are scarce.
Cats - lots of them - can help. Tiny, furry munchers, however, multiply at prodigious rates. Once again, poisons are dangerous and can be a slow, prolonged and unpleasant death for even vermin to endure. Quick-kill traps are probably the best and most effective. Orient traps so the creature MUST approach the bait from the end....not the sides. A standard mouse trap can be baited with something like half-cashews (salted...they love salty food) and placed between two bricks to prevent side-access. (if they come in from the side, they're apt to be caught by a foot or leg, then suffer for hours before perishing from terror or exhaustion.)
As you might expect, I prefer a more humane approach. Today, a wide variety of live traps are on the market and, since these little creatures adapt quickly, they can be lured into no-pain traps and you can transport them into a more wild location away from your garden. A mile would work... but not around other dwellings. Be very cautious, however, because almost all have fleas (that could be carrying disease) and could possibly carry rabies. Up close they're "cute" but don't be tempted to directly handle them.
By the way, both vermin and slugs are apt to be present in HUGE numbers - even if you don't see them. Get yourself ready for an extended battle.
Nibblers and browsers can be discouraged as well (deer, woodchucks and rabbits relish the fresh, crispy hosta leaves). A very effective deterrent is detailed in the article "Repelling The Rascals" on the web site.
Hosta As Houseplants?
Here's a question from one of our web site visitors, and my response:
Hello, Elizabeth....Thanks for your inquiry. There's really no valid reason to suspect that hosta wouldn't thrive indoors in containers—providing a few essential conditions are met.
Hosta have a very robust and large root system, and will need a container considerably larger than most common houseplants. Minimum 12" for a medium-size hosta. (Roots in improved garden soil will spread 18+ inches in all directions—including down—so give them some foot-space.)
A key—and inescapable—requirement is correct soil pH. Lime must be added to maintain nearly neutral pH (your State University Ag Department can provide reliable soil-testing service at a reasonable cost; contact your local Cooperative Extension Service for assistance and instructions). Any medium- to high-quality houseplant potting mix will suffice; add 1 cup of ground limestone to one 20-pound bag. Thereafter, add an ounce or so to the container once each following year.
Trim away all damaged, decaying, or unsightly foliage, and gently wash remaining leaves with a damp sponge or moistened, soft towel. Resist the temptation to coat foliage with products that're supposed to make leaves shiny...they can plug pores and, if used heavily, will attract even more dust...unless you like polishing leaves every week.
As you likely already know, moisture must be maintained—but not a "soggy-bog." And while you may wish to place a saucer or tray beneath each container to protect furniture, that saucer should never be filled with water. Irrigating should be done in a sink, where a flush of water is allowed to completely drain before return to the saucer. (Any sign of whitish-yellowish-brownish deposit around the container's lip or drainage holes is an indication of fertilizer salt buildup—and must be dealt with quickly: Scrape or soak deposits from all surfaces, place the container in a sink, tub or shower, and flush it out thoroughly.)
Hosta (and most other indoor plants) benefit from an occasional shower using slightly-lukewarm water. A shower stall or spray hose attached to the kitchen sink works well. Bathe them once every 2 or 3 weeks—removes dust and cat hair, serves to keep plant's pores open and efficient, and prevents salts build-up.
Every 3 months or so, add a teaspoonful of Osmokote (14-14-14 +/-) per one-gallon-size pot's worth of soil. (By the way, a standard "one-gallon" black plastic nursery container is actually 3/4-gallon. (I've been in the nursery business for years, but I'll never understand why most nursery operators insist on calling 3 quarts a gallon. There must be some slick 'n mysterious, big-city marketing tactic in play here! They use a 6-quart container for a plant, then call it—and price it—as "2-gallon!" Personally, I always feel significantly short-changed when I'm asked to pay $14.99 for a 2-gallon plant that's about the right size for a $6.99, 1-gallon pot.) Enough of that...back to basics:
Most hosta are grown in partial shade. A couple hours of very bright window light early in the day, followed by bright, conventional, fluorescent lighting during the remainder, should suffice. Be aware of drafts, especially during winter months. Allow your plant to "talk" to you. Continuous production of rich, dark green (variegated or other color) leaves, standing tall, lustrous and healthy say, "I really like it where I am!" Leaves which droop, hang, appear dull and possibly faded are saying, "Something is really wrong, here!" Improper pH? Insufficient moisture? Fertilizer salt build-up? Far too much light? Attack by hoards of tiny insects? Your job: Play Sherlock Holmes, then react accordingly. Far better, however, is to be pro-active—prevent problems before they occur.
Spider mites could present an annoying, but manageable, problem. Tiny insects (about 25-30 of the little critters lined up nose to tail might stretch an inch) mites usually congregate at or near the tips of new growth. Mites are piercing-sucking insects, and cause curling and distortion of leaves, and speckled discoloration on the upper surface. Most large garden centers and farm 'n garden stores carry a highly effective natural insect control called "Pyrethrin." That's the one; follow label directions, be sure to avoid inhaling spray mist, and wash up with soap and water when you're done. Yes, it's supposed to be natural and safe, but I still don't want anything in my mouth, eyes or lungs that can kill a bug. Indoor plants should never be sprayed with toxic pesticides for obvious reasons: children, pets, your lungs and bone marrow.That should give you some guidelines....it's really not as complicated as it sounds. Apply modest intelligence and common sense. Hosta are easy; they've been said to grow on a bald man's head! So, jump right in and enjoy.
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