Growing problems
with Hostas

 

Growing troubles with Hostas

Prelude

In general, Hostas are strong and easy growing, but it's not uncommon a plant doesn't grow bigger, but, surprisingly, gets smaller. This can happen gradually, but also very suddenly, e.g. when a plant emerges in spring.

Plant's that get smaller gradually

The cause usually is one of these three:

  • the plant is in an unsuitable place;
  • the plants gets to little nutrients or water;
  • the plant is in a container, but is unsuitable for pot growing.

The plant is in an unsuitable place

This problem tends to occur quite often with variegated plants that have little chlorophyll. This type of plants needs a lot of light to grow well. Positioning them in the sun allows them to grow better, but the lighter sections tend to melt out, resulting in an unsightly plant. This problem diminishes when the plants have lots of water available'
It's essential to find a perfect spot for them: lots of light, lots of water, just the right amount of direct sunlight.


Another common type of wrong placement is planting out your Hostas where there is a lot of competition from other plants.  This occurs when they are placed to close to a tree or shrub, or among strong growing ground cover. The surrounding plants take almost all of the nutrients and water',' leaving you with a dwindling hosta. If you have mad a bed under a tree, especially a shallow rooting one, it doesn't matter how much good soil, nutrients or water you supply; in the end, the winner (the tree) takes it all.  I've seen tree roots ('horse chestnut) entering the container of a hosta from below, leaving the hosta nearly dead within a period of a few months.
Moving the' hosta or removing or controlling the competition is the only solution.

The plant gets to little nutrients or water.

Hostas, it can't be repeated often enough, need a lot of water. When the supply is insufficient, growth will halt and the plant will dwindle.

A shortage in nutrients usually occurs with potted plants.  It can occur with plants that are planted out in the garden, but container plants depend entirely on what we provide. Use a good potting soil, neutral to slightly acid, free draining but moisture retaining.  Repot your plants on a regular base, at least every two years, and keep record of your repotting schedule.  It can be necessary to remove as much as possible of the old soil.

Some hostas just are not suitable for container growing.

  • Hosta's with H. 'Sieboldiana' or H. 'Tokudama' genes;
  • rhizomatous plants;
  • Hosta's with a' H. rectifolia background.

These are preferably planted in the garden

Plants suddenly get a lot smaller

A mature hosta needs a large, healthy root ball to maintain itself and to expand.
There are numerous reasons why a root ball can get smaller almost over night.  The plant will respond when this happens.  It can die, get a lot smaller or revert to a juvenile form.

Some possible causes

  • voles
    feed on the roots, quite often during the winter.  When -if- it emerges the next spring, it is reduced to a fraction of the old size.  Quite often it has sunk in the soil because of the tunnel system underneath. In most cases leaves will be smaller and margins more narrow, like a young plant.
  • frost damage
    quite often is the cause for suddenly decreasing container grown plants. As mentioned earlier, plants with' H. 'Sieboldiana' or' H. 'Tokudama' blood should not be kept in pots. During long periods of frost or late frost periods, when some plants already start to prepare for the new growing season, roots and growing tips can take a severe hit.'This is, in my opinion, the main reason for winter losses.  If not lost completely, the plant may show a distorted growth, often with small, deformed leaves.  To make matters worse, those weakened plants are an easy pray for viruses.
    If you want to keep plants in containers, take a few precautions: make sure the growing points are covered enough.  Potted plants can get heaved as a result of frost, leaving the crown and even the roots exposed.  Puts all pots together in a relatively sheltered area, protected from the cold winds. When late frost spells are announced, try to cover up the pots over night.
  • unsuitable potting soil
    for a number of years, I used to mix my own potting soil. After a couple of years it became obvious that a number of - often young - plants didn't make it through the winter like they should.  The soil mixture was to heavy and got water logged.  Especially at the end of winter, when the plants started to grow again the wet heavy soil, combined with the inevitable cold spells, was responsible for a lot of damage. Nowadays I use a good "standard" potting soil, bought in big bags (1 m3), and a coated fertilizer. There seem to be less losses and regrowing is much better.  Also, every new plant is repotted in this soil on arrival.

How to treat damaged plants

Treat them like seedlings or young plants. Remove all necrotic parts and plant them in a well prepared planting hole with a good soil, somewhere in the garden where you know hostas will thrive, or put them in a container with good potting soil.  Make sure they get plenty of moisture all the way through the growing season.