We have tree root problems that
markedly limit where we can satisfactorily grow any perennials. There is
an extensive network of greedy maple and other tree roots in both our
front and back yards. In time, hostas lose out in the competition for
water and nutrients, regardless of how well the soil is prepared prior to
planting and how well the hostas are watered and fertilized.
In addition, the large number of tall deciduous trees with their big leaves cast dark shadows almost everywhere all day. The earthen areas on our property that get enough sunlight to grow hostas satisfactorily are very limited. Heavy shade and aggressive surface roots from trees are among the worst conditions for growing hostas luxuriantly.
Another reason is what I call "staging." Sometimes you want a hosta in a certain dramatic location but if planted in the ground, the clump height is too low for the landscaping effect. Making a high-enough mound of soil for the plant to be planted in is not satisfactory. So the hosta is grown in a container to raise it to an eye level that compliments the surrounding planting. Often this container is very large and not moved for the winter.
Yet another reason is that young hostas, especially tissue-culture liners and difficult-to-grow varieties can often be best started in containers and grown on until they reach a suitable size for planting in the ground. And, if one is growing new cultivars for critical observations and side-by-side comparisons with other hostas, having them in containers where cultural conditions can be controlled is an advantage.
We have one hosta growing in a ceramic container. It is the small H. gracillima with long, narrow, wavy, green leaves. The glazed pot has drain holes and is decorated in a Chinese blue design. There is also a matching saucer. The hosta and pot complement each other nicely and make an interesting accent piece on the railroad-tie retaining wall of our patio.
The rest of our hostas in containers are in plastic pots. These pots are lightweight, just about unbreakable, very long lasting and cheap...usually free. Although there are some very attractive decorative terracotta-looking plastic containers on the market today, I prefer the green or black pots used extensively in the nursery industry. I think these colors look better with hostas than terracotta.
Additionally, for several reasons, I prefer the width of the pot to be greater than the height. First, my experience is that hosta roots mostly grow out laterally, and I want as much space for them to do this before hitting the walls and having to bend downward. Second, it takes longer for the hostas to become root bound in wide pots, so potting up is less frequent. (But don't put a very small hosta in a very big pot regardless of the pot's proportions.)
Further, I think
wider-than-tall pots look better with hostas because most have leaves that
spread out laterally or are fan shaped. The Tiara group, e.g., 'Golden
Tiara', 'Diamond Tiara' and 'Golden Scepter', look very nice in such
These pots are not easy to find and I have only a few. I make a practice of frequently examining the discard bins of local nurseries for them. One nurseryman calls them "azalea or rhododendron pots." Some containers intended for water gardens have these proportions.
Big plastic pots used for trees and shrubs often are this proportion or have a height about equal to width. I look for the ones with handles molded in. Our biggest plastic containers are about twenty-four inches wide and fifteen inches high. Two sit permanently in special locations in the garden.
I find that plastic containers about fifteen inches wide and high are about as large as I can move to a sheltered area for overwintering. We have huge clumps of H. 'Sagae' and 'August Moon' clumps in them.
These pots are sturdily built and have two handles molded into the sides. Two men can move them without much trouble even when the soil is water saturated. If I don't have someone to help me, I let the soil dry out a bit, rock the container onto an old piece of carpet, and then drag the rug with the pot on it.
A 15-gallon container, about
17" x 15", would probably require some mechanical equipment
assistance. These big sizes are often called cans or baskets in the
All smaller size hostas do well in containers, and there seems to be no restriction on how large a pot they can be grown in. The Tiara group, for example, does particularly well. We have had 'Golden Tiara' in 3-gallon containers bigger in size and better looking than the same-age hostas in the ground. Likewise with 'Platinum Tiara', the white-edged gold-centered form of 'Golden Tiara'; 'Golden Scepter', the all-gold form; and 'Grand Tiara', the wide-margined sport.
With just a few exceptions, all the bigger size hostas do well in containers, say two gallons and smaller, when the hostas are small. H. 'Great Expectations', interestingly, is one that I have not been able to grow well in pots greater than two-quart size. I seem not to be the only one who has made this observation with 'Great Expectations': I've heard the same problem from a wholesale nurseryman.
Therefore, the key question should be: What hostas do well in large size containers, say, 3- or 5- or even 10-gallon size?
By well, I mean that the hostas will get to about the same size and be as luxuriant as grown in the ground, assuming good cultural conditions, for about the same length of time. This implies the containerized hostas were potted up (properly should it be “up potted”?) when they became root bound.
My experience indicates that any hosta can do well in large containers and reach a fairly large size – except many, if not most, of the H. 'Sieboldiana' types. I have not been able to get 'Elegans' to a large size, nor also 'Northern Halo'/'Northern Exposure', 'Great Expectations', 'Tokudama', 'Tokudama Aureonebulosa', 'Tokudama Flavocircinalis', 'Golden Bullion' and 'Golden Medallion'.
Some time ago I stopped trying to grow the sports of 'Elegans' (such as 'Frances Williams'), 'Tokudama' or any hostas with strong H. sieboldiana lineage in large containers. I think it has to do with the thick ropelike roots and their being confined. Perhaps one should root prune these hostas each year as was done with fruit trees growing in containers in the opulent days of Louis XIV.
Some big hostas that I have been able to get to a fairly large size in large containers include H. 'Sagae'; H. ventricosa 'Aureomarginata'; H. montana 'Aureomarginata'; 'Fortunei Aureomarginata'; 'Gold Standard'; 'August Moon'; 'Sugar and Cream'; 'Sweet Standard', the streaked sport of 'Sugar and Cream'; 'Blue Angel'; 'King Michael’; 'Antioch'; and 'Daybreak'.
This bark potting mix is
lightweight and does not compact. it has a very open, porous, crumbly
structure. Air and water are easily captured in the voids. Drainage is
good. In time the bark breaks down; drainage decreases and water retention
increases. I’m told it takes about four, maybe five, years for the bark
to more or less fully decompose in a heavily rooted pot that's abundantly
watered and fertilized.
Hosta roots love this bark potting mix. A massive fibrous root system easily develops. As long as the pot is watered frequently, perhaps twice a day in the South, and fertilized frequently, perhaps as often as once a week or more, this may be as ideal a potting mix as one can find.
When one takes a hosta out of a container with this mix, the bark (and sand) can often be shaken from the root ball. Sometimes I've noticed that the roots actually attach themselves to the bark pieces. (There is some question as to how well plants grown in this potting mix do when planted afterward in the ground.)
Comments: [For more than ten years I have not found Jungle
Growth in my local nurseries and garden centers. Probably because of a
superb marketing effort along with a comprehensive nationwide distribution
network, they mostly only offer products from the Scotts Miracle-Gro
behemoth. So I went over to using “Miracle-Gro Potting Soil” because
it is readily available in super large bags and heavily discounted in
big-box stores. It is largely peat moss with perlite, which I don’t like
because of its too-noticeable white color. But all in all it is a good
soilless mix. Though it contains some fertilizer, the amount is not enough
for hostas and must be supplemented. ]
[Recently my preference has been a fairly new product called “Organic Mechanics Container Blend Potting Soil.” It is 100% organic and has no peat moss. It contains compost, pine bark, coir (coco fiber) and, interestingly, worm rice hulls. This soilless mix doesn’t break down as fast as peat-based mixes, holds moisture well and has excellent drainage. You do have to water often. Availability is somewhat limited. Check it out on the Internet: www.organicmechanicsoil.com .]
The grit adds further
drainage and air retention. Although Miracle-Gro doesn’t need grit if
plants are in containers for only a year, maybe two. My experience is
grit is needed if kept longer because the peat then breaks down and
drainage markedly decreases.
By grit, I mean chicken grit, crushed granite sold as a supplement for feeding poultry. I buy it in 50-lb bags. The brand name is "Gran-I-Grit" and comes in several sizes. The Starter size, I think, is too fine; I use the Mid-Grower size.
A soilless potting mix containing one-quarter grit is a heavy mixture. A water-saturated 10-gallon pot is just about too heavy for me to lift. Perlite, vermiculite and polystyrene beads are all feather weights in comparison to grit, which is a reason why mixes containing them are popular with both home gardeners and the nursery trade.
In a bushel-basket-size
container of the potting soil, I add fertilizers and other
“goodies.” If potting is done in the spring, I add a small handful
of a controlled-release fertilizer, "Osmocote," readily
available in garden centers. About half of the handful is "13-13-13
Plus Minors" stated to last up to 4 months. The other half is
"17-6-10 Plus Minors" claimed to be "270-day Foolproof
Feeding." [Product labels have changed over the years. Still,
you’ll probably find the current labels have about the same
nutritional contents. My experience indicates Minors or trace elements
are beneficial, so look for fertilizers with them]
I also add two big handfuls of greensand. This is mined in New Jersey and fairly easily obtained where I live. It's a marine deposit with potash, silica, iron oxide, magnesia, lime, phosphoric acid and numerous trace elements. [Pete Ruh in Chesterland, Ohio, extolls it and he grows great hostas.]
I further add a handful of black rock phosphate. Black rock phosphate contains only 4% phosphoric acid. That's not much phosphorus so I add two handfuls of bone meal (1-12-0), or a small handful of superphosphate (0-20-0), or a half of a small handful of triple superphosphate (0-46-0).
Then I add a handful of powdered kelp, sea weed. This elixir is supposed to stimulate growth and improve stress resistance. Organic gardeners swear by it – and so do I.
Finally I add a half handful of alfalfa meal.
Added to the solution is half-strength “Peters 30-20-20 Orchid Special.” I don't use "Miracle-Acid" 30-15-15 or generic equivalents for acid-needing plants. The pH is too acid. I sometimes use regular "Miracle-Gro" or generic equivalents with 15% nitrogen at full strength. [I want a quick acting fertilizer – but not too much of it.]
To each gallon I also add 10 drops of “Superthrive,” another tonic with great claims: "all essential vitamins, hormones and other extra factors."
Also added to each gallon is 1 1/2 tablespoons of the systemic fungicide “Bonomyl” from Bonide, which is similar to “Benlate.” [Benlate is not available anymore, nor is Bonomyl. Bonide's new consumer product is called "Infuse". The general purpose, fungicide “Cleary 3336” can be substituted.]