Proper planting provides hostas with good growth, and they will feel comfortable for a long time. However, the incorrect planting depth can lead to plant loss.
The hosta should be planted to a depth so that the crown was at the surface level. Dig a hole twice as big as the root ball of the hosta and fill it halfway with well-drained soil. Plant the hosta so that the stems do not become buried in the ground.
Next, I will tell you all the intricacies of proper planting depth and what can happen if you do something wrong.
Do not deepen the crown
Planting hosta, you do not want the petioles and the center of the crown to be covered with earth. If you bury your plant, then it can start to rot.
First, you need to dig a hole where the hosta will grow. I recommend digging a hole twice the size of the container in which the hosta grows. If you transplant it from another place to a new one, the size of the pit should be twice as large as the rhizome in both width and depth.
This size of the pit is needed to make it easier for the plant to penetrate the roots because the soil around will be loose. So the plant will quickly establish itself in a new place.
Next, you need to prepare the soil mix. The best will be a mix of compost and garden soil (loam, etc.). The proportion of these two components should be 50% to 50%. Use good compost made with the right technology. Otherwise, you may damage your plants. Poor quality compost can contain not only diseases and pests but also aggressive substances that can easily destroy the roots.
Fill the hole with the prepared soil a little more than half. Place the hosta with the roots in the center of the pit. The place where the petioles connect with the rhizome should be slightly higher (0.5-0.7 inches) above ground level. This is necessary because, over time, the soil under the plant will settle a little, and the crown will be on the same level as the ground.
Next, fill all the free space around the roots with a prepared soil mix. Compact the soil a little and, if necessary, add more. As I mentioned, the soil should not be above the base of the petioles, also do not pour the ground in the center of the crown.
Water the plant with plenty of water. After a while, the water will come down, and the ground will settle, so you will need to sprinkle more soil mix. Then water the hosta again.
In autumn, the leaves wither, and you need to remove them, do not let them rot around the plant. As a result, dormant buds will be above the ground. You do not need to worry that they can be damaged by frost, the hosta is a very hardy plant. However, there may be other problems.
When winter comes, the plants go into hibernation, and the sap flow in them stops, they live on internal water supplies. Sometimes it happens that there is no snow, but the sun shines quite strongly. As a result, buds can lose too much moisture. In addition, in the absence of snow, frosty winds can still cause some damage to hostas, especially in the north of the United States.
To avoid winter damage, you should mulch the hosta. It is best to use compost or pine bark. In late fall, pour a thin layer of mulch (no more than 1 inch) on top of the crown. This will protect the plant from drying out. In the spring, you should remove the mulch from the top of the crown.
What if too deep?
The reasons why the crown of the hosta may be underground are different. The first and most common reason is the wrong planting, to avoid this plant hostas properly, I wrote about it above.
The second reason is the subsidence of the soil under the plant. This often happens because the soil in which the hosta grew was very loose. In nurseries for growing hostas use a very loose substrate based on peat. In such conditions, the plant grows quickly and has a good appearance.
However, if you buy a hosta in such a substrate and plant it in the garden even on the same level as the surface, after a while, the commercial substrate will collapse, and the plant will be in the depths. To avoid this, before planting, remove the hosta from the pot and shake all the loose soil but do not damage the roots.
Next, plant the hosta in the soil mix with solid soil (such as loam). You can read more about this in the previous chapter.
What to do?
Suppose for some reason your hostas are too deep in the ground. The first thing you need to do is remove the layer of soil around the petioles so that they do not sit below ground level. Remove excess soil around the bush at a distance of 4-6 inches or even more if needed. Try not to form a hole near the plant; make the deepening gradual.
However, this is a temporary solution, because there will still be a depth near the rhizome and water will collect there. As a result, the petioles and crown may rot. Therefore, you should transplant the hosta higher.
Dig a hosta with the maximum number of roots, try not to damage the plant. You can plant in the same place. Pour a layer of soil into a hole 1-2 inches high (or more if needed), then place the hosta on top and cover everything around with soil.
If the hosta is a little higher, nothing terrible will happen, it is better to be higher than deeper. Although here, I must say that often young shoots begin to grow out of the ground. As a result, they are buried in the ground at 0.5-1 inch, and in most cases, nothing bad happens to them. Despite this, I still do not recommend deepening the hostas at all.
For large varieties of hostas, a slight deepening (up to 0.5 inches) is not too critical. Their rhizome has a lot of strength, and young shoots will break through the ground.
However, for dwarf and miniature varieties, even a small amount of soil above the place where the rhizome and petioles meet can be fatal.
Too deep planting can cause rot
Usually, in the situation of deepening, the lateral petioles begin to rot first. The rot begins at the bottom, and the leaves turn yellow. Then the petiole breaks under the weight of the leaves and falls to the ground. In this situation, it is not too late to save the plant.
As soon as you notice that the outer leaves have begun to turn yellow, immediately check that the ground is not above the base of the petioles. If so, remove the soil layer, as I wrote above. Then tear off the damaged petioles. In the early stages of the disease, the crown does not begin to rot, and only individual petioles are affected.
After cleaning the plant, spray it with a solution of fungicide. After a while, repeat the spraying. Also, spray the ground around the hosta.
If you notice the problem late and the plant is affected too much, then you should dig it out and clear all the soil from the roots. Wash all roots with water and use a sterile instrument to remove all affected tissue.
Next, pour the hosta with a fungicide and dry a little in the shade. Then plant in clean soil (in a pot) and transfer under the roof in the shade. A waterproof cover is needed to control the amount of water the plant will receive.
Water the hosta moderately. The recovery process can take 1-2 years.
The roots can come out of the ground.
Sometimes it happens that the temperature often changes in winter. Frost and thaw are repeated over and over again. As a result, the upper part of the roots of the hosta are pushed to the surface, and you can see the roots. This often happens with small varieties.
If you have a similar situation, just add a little soil to cover the roots. Also, pour a thin layer of mulch around the hosta. If the roots are too high, then you should transplant the hosta deeper.
How deep should soil be for hostas?
Hostas need deep soil because they are moisture-loving plants and their root system penetrates deep to extract water.
However, if you grow them in pots or trays, then the depth does not matter much. Compact varieties can grow in pots 6-8 inches deep, and larger varieties need 10-12 inch containers.
Timely watering is more important here. In dry and hot weather, a pot with a hosta can dry out in one day. So make sure you water them on time.