Miniature and Very Small Hostas
Miniature or Very Small?
Most hosta collectors think of a miniature hosta as one which grows no more than about 15-18cm (6-7”) in height. However, the American Hosta Society (‘AHS’ in our Catalogue entries) which sets the international standards for hostas now defines a miniature as one which has a mature leaf area of 6 sq.” (15 sq. cm) or less. This means that some varieties with long narrow leaves of 15 sq. cm. or less, are designated as minis even though their mature height may be up to 30cm (12”), for example H. ‘Stiletto’ and H. Hacksaw’. Our own experience also shows that some AHS designated minis grow larger than their given size: e.g. H. Blue Cadet, H. Kifukurin Ko Mame, H. Lakeside Down Sized.
Because this can be misleading for customers choosing minis to plant with others in bowls and troughs, from 2018 we have re-designated the taller AHS miniatures (those that commonly grow over 18cm (7”) in height as ‘Very Small Hostas’. Hostas listed in our Catalogue as ‘Miniature/Very small’ hostas are those that fail to meet the AHS requirement for leaf size but still have a mature height of about 15-18cm (6-7″).
Choosing Miniature and Very Small Hostas
If you are just starting out with miniature hostas, click on the ‘Select Other Characteristics’ box at the top right of the Catalogue and then click on ‘Top 20 Miniature Hostas’. If you already have a collection, click the ‘Select Hosta Categories’ box at the top left and then click ‘Miniature Hostas’ The Catalogue will then show only miniature hostas. Repeat for ‘Very Small Hostas’. Once you have the ‘Miniature’ or ‘Very Small’ catalogue in front of you, clicking one of the ‘Select’ boxes refines your selection by colour, leaf shape, etc.
Please read our Catalogue carefully…
Our Catalogue gives both the expected mature height and average mature leaf size of miniature and very small hostas grown in the open ground, in good light, with unrestricted root-room.
We have many years’ experience growing minis for our own collection of 100+ so please read our notes on each variety carefully. (Click on the main photo for each entry for extra information). Many ‘Very Small’ hostas are still suitable for troughs and bowls since, like many vigorous miniatures, they very conveniently ‘bonsai’ themselves if their root-room is restricted. That is, their height and, often, leaf size, is reduced. If we think this is true of a variety, then our notes will say so.
Miniature hostas look great planted together in bowls or troughs, separately in pots, or in gravel beds. Some of the more vigorous varieties also look good as edging plants or on rockeries, but since they do not spread rapidly make sure they can’t easily be smothered by faster growing and spreading plants.
Most miniature Hostas are trouble free and, like their larger relatives, are very easy to grow. If a variety needs any special care or is not easy to grow well, then our Catalogue entry will say so (click the main photo for this information.)
Always buy ‘difficult’ minis early in the season, to give them a full seasons growth before winter.
The secret of growing miniature hostas well is to make sure they have very good drainage. Miniatures need a lot of air around their roots and hate sitting in water-logged compost over winter when wetness combined with a hard freeze can cause root rot. Since miniature and very small hostas often have fine and shallow roots, you also need to make sure they do not dry out during the growing season.
Miniatures like a light, well-aerated growing medium so if your garden is peat-free then you will need to add about 40% horticultural grit, sharp sand or potting bark to organic composts. Even if you plant using a peat or peat substitute compost you will need to add about 20% of other materials It really isn’t important what particulate you use, providing it is inert. After ten years of planting in our gravel garden, miniature and very small hostas seem to thrive on a mixture of 50% compost, 50% pea gravel, which invariably falls into the planting hole with every new planting! It is always useful to add some garden soil to fresh compost. Hostas benefit from mycorrhizal fungi which occur naturally in garden soil. If you plant in compost alone you can buy mycorrhizal fungi as granules or powder on-line and in good garden centres (Rootgrow). Mycorrhizal fungi help improve root growth.
Open Ground Miniature/Very Small Hosta bed at the foot of a rockery
Raised bed for Minis and Vary Small Hostas
Miniature Hostas in Troughs and Bowls
The natural spread of miniature hostas varies, but given enough root-room and good growing conditions most will reach a diameter of 30cm or more (12”+) when mature, far too big for most bowls and troughs. The good news is that miniature and very small hostas may take 3-4 years to reach this stage so even vigorous minis can be displayed together for at least two years before they need dividing. If planting in a trough or bowl make sure it is deep enough to allow a layer of pea gravel beneath the growing medium to aid drainage. 4-5” depth of growing medium will ensure that your miniatures will grow well. Also make sure it has plenty of drain holes. You may have to drill some more.
If you are determined that you want the tiniest minis possible for a small trough or bowl, it is sometimes a mistake to choose those in the Catalogue that seem to have the smallest mature height and leaf size. Often the smallest minis are those most difficult to grow well. These are the varieties that need to develop the largest root ball possible to thrive. In a trough or bowl with restricted root-room and competition from other minis they will probably struggle. Minis with a large amount of white in their leaves also fall into this category: e.g. H. Lakeside Elfin Fire, H. Pandora’s Box.
So, for the smallest mature plants, it is better to select a vigorous mini or very small hosta that will still grow well, even if its root ball is very restricted. Some miniature and very small hostas make wonderful accent plants for bonsai or look good by themselves in the smallest bonsai or accent pots. When planting in a very small pot, or accent pot, good drainage is even more important, to assist watering, so two parts compost to three parts horticultural grit should be used. Regular watering is important. After a year or two check the roots. If the hosta has pushed itself out of the compost. or is pot-bound, root prune, as you would a bonsai tree, adding fresh compost under and around the hosta.
Mature Miniature Hostas in 2” deep Bonsai Pots
Of course, miniature and very small hostas do not just look good planted together. We have found bulb bowls to be an excellent way of displaying minis, using ‘hosta theatres’ to raise them off the ground. Again, holes may have to be drilled in them for drainage. The bulb bowls in the photos below are plastic, painted with an exterior paint.
If you are growing mini and very small hostas in bowls or pots, check at the beginning of the season to see if their roots are filling the pot. If they are, then tease out some of the old compost and replace with fresh, adding slow release fertiliser granules to the new compost. If the plant is pot-bound and you don’t want to divide or re-pot it, then root prune it by snipping off some of its roots with scissors and fill the space released with fresh compost as above.
Miniature and Very Small Hostas in Bulb Bowls
Miniatures, like all hostas can be given an initial boost by using a weak seaweed feed (root stimulant) between March and May. White centred minis, i.e. those with little chlorophyll in their leaves, benefit from a weak feed through the summer, but do not feed after July, when the hosta is beginning to slow down for the winter. When choosing a fertiliser, choose one with 10-20% nitrogen content.
The best time to divide minis is when they are growing most strongly. In the UK this is from May to June. Before you divide, check that the root ball is a good size and that the plant has multiple eyes (leaf buds). Some miniatures can simply be teased apart, without using a knife. Try this first before you resort to cutting. If you need to cut through the crown of the mini to divide it, then use a sharp kitchen knife or a cheap disposable blade craft knife. Cut carefully through the crown and tease the roots apart. The rule for dividing is: ‘Don’t be too greedy!’ The more divisions you try to get out of one plant the more chance there will be of losses. Some hostas increase in size through underground runners. These are usually the easiest to divide since there is no central crown to cut through. When you buy a miniature hosta by mail-order either bare-root or in compost, or when you divide, you will sometimes find little plantlets fall away from around the main stem. Don’t be tempted to plant these separately. They are likely to die.
Over-wintering miniature hostas
All hostas benefit from about 4-6 weeks dormancy in winter – temperatures below 4C. or 40F – so over-wintering minis outside in a severe winter isn’t a problem providing they have very good drainage. Cold won’t kill a mini but being waterlogged, frozen, thawed and frozen might, particularly during its first year of growth. Mulch your minis with bark chippings or horticultural grit to help prevent crown rot and the puddling of water around the crown if there is a top thaw after a really hard freeze.
Many people bring minis planted in troughs or bowls under cover during winter. A porch or car port is ideal. This protects the hostas from getting waterlogged by thick snow and winter rain and makes sure they get plenty of ventilation. This minimises the risk of crown rot. Never bring minis indoors – even into a conservatory. In a cold greenhouse it is best to keep the doors and window vents open unless it’s blowing a gale. Put your minis outside again mid-February, unless that coincides with a severe cold spell, and water from then on.
These notes can only cover the basics. If you have any questions please give us a ring:
Tel 01484 866189,
Mobile 07917 006636