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Hosta (HOSS-tuh)

Common Name:  Hosta, funkia, plantain lily

Light:  - Part sun to full shade

Soil:  Humus-rich, moist but well-drained

Moisture:  Average to consistently moist

Blooms:  Mid and late summer

Zones:  3 - 9

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Hosta Krossa Regal
Hosta 'Krossa Regal'
Hosta Radiant Star
Hosta 'Radiant Star'

General Hosta Growing Information

Selecting a Location

Hostas are some of the best plants for shade. They add lush foliage to shady areas in northern climates, almost as if the garden was a tropical paradise. Still, many hosta plants do tolerate the sun, especially hostas with fragrant flowers. When planting them in the sun they will need a lot moisture, and if your plants do get sunburn then move them to more shade.

Soil

Hostas love to grow in very rich soil, and even do well in heavy, moisture retentive soil. For the best success, enrich your soil with well rotted compost, well rotted manure, peat humus, or aged pine bark mulch. Add peat moss or hydrosource crystals to help with moisture retention in well drained situations. When we plant hostas we add a handful of high phosphorus fertilizer (such as 5-10-5) to the planting hole and mix well with the soil so it can establish a good root system upon planting. We also add alfalfa to our hosta gardens as it contains an growth hormone that stimulates hosta eye production.

Planting

Spread out the roots so that they are not coiled in the bottom of the hole. Sometimes forming a cone of soil in the bottom will make it easier to place your hosta in the hole and spread out the roots over the cone. Plant so that the crown and roots are completely covered and the tips of dormant eyes are completely below the surface (see guide below). When planting hostas that are already leafed out you should keep them at the same level they were previously growing. If the stems are planted too deep then the outer leaves will usually rot and die off however new leaves should grow back to take their place if that ever happens, as the plant adjusts to the new depth.

General Crown Depth

Mini: 1/2”, Small: 1”, Medium: 1 1/2”, Large: 2”, Giant: 2 1/2” (from surface to the top of crown or base of the eyes) Note: Dormant hostas should not have any eyes showing after planting since dormant buds only grow below the surface. Some plants grow eyes horizontally and these should always be buried completely. Red stemmed hostas should be planted about 1/2" deep as they are more sensitive to rot from moist or compact soil.

Moisture

Keep your hostas moist but not too wet. They don't mind having their roots in water, but the crown should stay relatively dry and its best to let the soil dry slightly between watering. Early season flooding will not hurt hostas as long as the water recedes later. In the wild hostas receive about 1" of rain per week and it is best to give a good deep watering once or twice a week rather than light watering more often to encourage deep, strong roots. If your hostas do not get enough moisture then they can eventually suffer dry rot. When this happens the roots dry out and rot off from the crown. The crown will actually shrink over the course of the growing season. Unfortunately because much moisture is stored in the leaves the effects of dry rot will not always be apparent until the following season. If your hostas suffer through a drought and then come back smaller the following year then they have most likely suffered dry rot.

Care

When mulching your hostas, don't allow the mulch to cover the crown or touch the leaf stems as this can cause rot. Form a ring of mulch around the base, just covering the roots, without getting close to the crown. Hostas are heavy feeders so keep fertilizer away from the crowns. Feed sparingly but feed often. If you use water soluble fertilizers, mix it very diluted and only fertilize after the plants have been watered to avoid damaging them. Established hostas enjoy a high nitrogen feeding early in the season, but require balanced feeding as the season progresses. Too much nitrogen can cause leaves to be thin and weak making them susceptible to damage from slugs, wind, or rain. Stop feeding hostas in late August or early September so you don't encourage new growth near the first freeze. In the fall, allow your hosta leaves to experience a hard freeze so that the foliage dies back naturally. After the foliage has completely died back then it will easily pull away from the crown with a rake or with your hands. Discard or burn the old foliage to reduce the risk of overwintering foliar nematodes.

Division

Hostas can be divided from the time they poke out the ground up until September. Divisions made during the heat of the summer will need more moisture to get them established, but they will bounce back quickly. Avoid dividing plants too late in the year. Crowns that are cut need time to heal before winter. Plants that have been cut in the fall may not heal until the following spring, allowing a greater chance of crown rot from bacteria or fungus during the winter. Fall division and transplanting will be much more successful if you don't damage or cut the crowns in the process.

Slugs and Snails

A major enemy of the hostas are slugs and snails. To prevent damage, sprinkle slug bait around the base of your hostas or place a saucer of beer in the garden to trap them. Pick them off when possible, and keep the garden free of excess debris so they don't have too many hiding places. Use slug bait sparingly as it may be toxic to dogs and other animals, and if you use too much in any one spot you may attract more slugs to the garden. The best time to spread slug bait is in the fall during an Indian summer (above average temps following the first frost). By killing the slugs in the fall you will greatly reduce the overwintering population. Repeat your slug bait application again in the spring just as the eyes start to sprout. The fall and then spring treatments should help to eliminate most summer damage.

Voles

Voles are types of field mice that love to eat hosta crowns, especially in the winter. To prevent vole damage, place traps along vole runs or put rodent bait in the area. (Make sure other animals can't get the bait as it is very poisonous). Or, get a cat that likes to hunt. And once again, keep the garden free of debris so that the voles don't have good nesting places. Especially clean up debris from ornamental grasses as voles love to build nests in old grass.

Deer

Deer can ravage a hosta garden in very little time. To repel deer you can spray the hosta foliage with hot pepper wax, dust the foliage and entire garden with bloodmeal, sprinkle mothballs around the garden, and spray with Liquid Fence (a mixture of garlic, rotten eggs, and soap). Vary your plan of attack and start out doing these things weekly for a few weeks in the spring and then repeat something each month. In time the deer will change their traffic pattern and avoid the garden completely.

Foliar Nematodes

foliar nematodes on hostaFoliar nematodes can be another problem although they will never kill the plants. Yellow to brown streaks may show up between veins in July through September indicating that the nematodes were feeding. The further south you are, the sooner the damage will appear. Good culture is the best solution to prevent plants from becoming too badly affected. To prevent the spread of nematodes, clean all tools when cutting, dividing, or trimming from one plant to another. Also avoid overhead watering as the nematodes can be spread by splashing water. Do not compost the leaves as the nematodes may live in the compost. And remember, nematodes will always flow and collect wherever the water runoff goes. Keeping hostas uphill from other plants can help to prevent nematodes infestations. And keep an eye on hostas in low lying or wet areas as these will be the first plants to show damage.

If a plant becomes infected and it can be easily replaced you might want to destroy the entire plant. Spraying with Diazanon or hydrogen peroxide (1/2 cup of 3% H202 per gallon used as a foliar drench) can be effective at killing some nematodes but will not kill them all and should be repeated 2 or 3 times every 10 to 14 days. Orthene may reduce the active nematode population by about 60%, but none of these chemical treatments kill the eggs. The best way to destroy nematodes and the eggs in an infected hosta is to soak the entire plant in a warm water bath. Soak for 10 minutes in a 120F warm water bath or 5 minutes in a 130F bath. After soaking, immediately rinse with cold water to stop the cooking process.

Hosta Virus X (HVX) Information

Hosta Virus X has developed into a major problem over the past several years, and is probably the number one threat to hosta collections around the world at this time. It will cause strange mottling, spotting, and even distortion on hosta leaves. It will never kill the plant, but it may struggle to grow and will look worse and worse as it becomes more infected. Thousands upon thousands of infected plants have been distributed by major wholesale hosta suppliers into the US, so if you have purchased many hostas in recent years there is a chance that you have it in your garden. Some infected plants have even been named and sold specifically because of their bizarre coloration, such as Hosta 'Leopard Frog', Hosta 'Eternal Father', Hosta 'Kiwi Watercoulors', and Hosta 'Breakdance'.

The primary mode of transmission of the virus is through damaged roots and leaves, though transmission in soil containing infectious roots is also possible. When an infected plant is cut with a knife or shovel the virus may be carried in the sap and then transmitted when the tools are used to cut into a healthy plant. Additionally the virus seems to be transmitted in handling and cleaning. In Holland roots are cleaned with pressure washers where the water is used over and over again, and it is speculated that this could be the source of the major infection coming out of Holland. When an infected plant is washed the root tissue collects in the water and then passes the virus to any plant that is washed afterwards.

If you discover that you have a plant infected with Hosta Virus X then the plant should be dug up and sent to the landfill or burned. Dig the entire plant getting as much of the roots as possible. Do not put another hosta plant in the same hole unless you are certain you dug out the entire root mass and replaced all the soil with fresh dirt. Also it is best to dig out your plant in the fall, if possible, as this is the time of year when the possibility of transmission is at its lowest.

To prevent spreading the virus, always disinfect your tools with a cleaning product such as lysol or alcohol after each use, being certain to scrub off all of the plant sap. This includes scissors and pruners when removing scapes or leaves, shovels or trowels when digging or dividing, and even your hands when touching the sap from any plant. Disinfecting wipes work great for scrubbing off tools.

In addition you may not want to soak hostas together in the same bucket when you get new plants in by mail. This might lead to spreading HVX as the plants have been freshly damaged in the shipment process and it can also spread nematodes. If you need to rehydrate hostas soak them individually in their own buckets or containers in fresh water for each plant.

If you suspect that you have a plant with Hosta Virus X but you are not completely sure you should contact your local extension office or a local university to see if testing is available. Visual diagnosis is also possible by posting pictures to the various online forums and discussion boards.

You can view many more pictures on the Hosta Virus X topic or ask questions on the Hosta Virus X forum.

Hosta Landscape Uses

Plant Hostas with ferns, woodland anemones, Astilbes, toad lilies (Tricyrtis), Lamium, Pulmonarias, Tiarellas, and other shade loving plants. Use Hostas as specimens or accents, ground covers, edging plants, or background plantings . Plant small Hostas in rock gardens or containers. For a care free bulb garden place tulips or other spring bulbs around the base of Hostas. As the old bulb foliage begins to die away the new Hosta foliage will hide them.

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