Yes, Mulch Does Matter!
For hosta to thrive and reach their full potential they need a constant moisture supply through the growing season and a soil rich in organic matter. Hosta located in dryer soils will grow more slowly, put out fewer leaves and not look as lush especially during the summer months. Location, location, location is all important. But you can improve the location by digging deep and incorporating as much as 50% compost to the soil mix that goes back into the hole. This compost will improve fertility, water retention and provide drainage during heavy rains.
A mulch that is already partially decomposed is also beneficial. Over time this adds more organic matter to the underlying soil. Fresh hard barks or wood chips can be detrimental to hosta if you are not supplementing them with a nitrogen fertilizer. A better mulch for hosta is something like aged Dark Bark, aged manure or more compost. Some of the better garden centers will have bagged product that is a mixture of compost and aged bark. Freshly milled bark ties up nitrogen in the root zone as the soil bacteria begin to work on decomposing the bark.
If you add the proper amounts of organic matter previously described, your hosta will not require a lot of fertilizer. An organic fertilizer such as fish emulsion or processed chicken manure is ideal. Follow the label instructions and all the nutrients will be retained in the soil by the organic matter. If you prepare all your hosta beds this way you will observe that the best growth is obtained in the areas with more moisture. Growing the larger varieties in these areas would be best since they have heavier moisture requirements.
Planting Bare Root Hostas and Companion Plants. If you live in a state that we have to ship bare root plants to, here are some instructions to help you succeed. Plant your new plants right away! The bare rooted plants must be planted asap for best results. They will arrive in a plastic bag with the roots wrapped in wet newspaper. It is very important to not let the roots dry out before planting. Remove the plant from the plastic bag and remove the wet newspaper from the roots. Dig a hole about twice as wide and deep as the root system and follow the planting instructions above for incorporating organic matter. Partially backfill the hole with your soil mixture creating a mound in the center of the hole. Spread the root system over the mound you created with the crown of the plant sitting on top of the mound. Backfill the hole with the remaining soil making sure to get the soil evenly around the root system. We usually hold onto the crown of the plant and shake the plant as we backfill to get the soil in between all the roots. As you backfill you can adjust the height of the crown of the plant by moving it up or down. All of the roots should be below ground completely covered by soil. Where the roots meet the crown of the plant should be at or just below the soil level. We usually leave a ring of soil about 1-2 inches tall around the newly planted perennials to keep any water in the immediate area. This makes sure that any water that is given to the plant goes straight down into the root system and does not run off. You can fill this ring a couple time after planting. You will want to water your newly planted plants every other day for a week or so. Then you can water them twice a week for a few weeks until you feel they have adjusted to their new location.
Light Levels Matter!
Different hosta selections will have different light requirements. Here are some generalities by leaf color, but it is best to research your selections to determine their preferred light levels.
- Blue leaved hosta retain their color best in shadier areas where the sun does not penetrate between 10 am and 4 pm during the summer months.
- The gold leaved hostas can generally tolerate sunnier locations but even they can show sun scald if they receive too many hours of mid day sun.
- The variegated forms in general prefer light conditions somewhere in between the afore mentioned blues and golds.
Hosta will make grow faster with more exposure to sun. However, this is at the risk of leaf damage that will be visible for the entire season. Morning sun with some early afternoon sun will maximize the fragrance produced by the fragrant blooming cultivars. Ideally these like 5-6 hours of total sun.
Keep these generalities in mind when you choose your location. Look up a particular hosta to see the ideal location. Do not hesitate to move them in the future if you observe too little growth in the shade or too much leaf scalding in the sun. This is all part of the fun of gardening. Have fun!
A question we get asked often is what fertilizer to use on the hostas. First and foremost we start this answer with amending the soil with compost. Incorporating compost into the holes when planting is the best fertilizer you can start with. That being said, if you want your hostas to grow to the best of their ability, a balanced fertilizer applied each year is key. As for what kind of fertilizer to use, the answer depends on the kind of gardener you are. If you just want to put a fertilizer down in spring to help the plants and be done with it then a slow release granular fertilizer is adequate. A common granular fertilizer has an NPK of 10-10-10. Those 3 numbers on a fertilizer bag which stand for Nitrogen, Phosphorus and Potassium. The slow release fertilizers slowly feed every time you water or it rains. They generally last about a month to two months depending on temperatures and how much water is applied. Be sure to keep the granular fertilizer off of the leaves and crown of the hostas as they can burn. That's why it is best to apply this fertilizer before the leaves unfurl.
If you want to get a little fancier and get the best growth out of your hostas then constantly feeding them through the spring months is key. I like to apply a slow release fertilizer as previously explained but I also like to apply a liquid feed every week to every other week for a quick boost. A liquid feed gives the plants a boost but only lasts 24-48 hours as it is either absorbed by the plants or leaches into the soil. I also like to mix a couple tablespoons of Epsom Salts to my liquid fertilizer. Epsom salt is made up of "hydrated magnesium sulfate" (magnesium and sulfur), which is important to healthy plant growth. Magnesium allows plants to better take in valuable nutrients, like nitrogen and phosphorus. It also helps in the creation of chlorophyll, which is vital for photosynthesis. Hostas love magnesium and therefore enjoy a shower of Epsom Salts. It easily dilutes in some warm water and can be mixed with any liquid fertilizer. When fertilizing please read the instructions and DO NOT over feed! More fertilizer does not necessarily equal bigger plants. It can actually do the reverse and burn the roots and damage if not kill the plants. If you water often then you will need to fertilize often as well because watering leaches the nitrogen away.