Hosta 101

Hosta maturity

A hosta plant generally reaches full maturity in 4-8 years. Plants for sale at our nursery are in the juvenile stage. They only show a small view of what they will look like at maturity, compare it to when you were a child to what you look like now. Maturity brings full leaf size, corrugation, cupping, rippling and colour depending on the variety. From my experiences in my own hosta garden I find that the first years the hosta clump grows and gets larger and looks great; then one year it matures and the plant takes on a whole new look. Hosta 'Patriot' as an example the first few years was growing nicely but I didn't see anything that great about the overall look of the plant. Then one season it matured and it was stunning; the nice upright, crisp look of green leaves with wide extra white margins. So be patient your hostas will grow to surprise you.

Hosta origins

Hostas originated in Japan, China and Korea and either came from the lowland areas or the mountain areas. They were first introduced to Europe in the late 1700s and then came to North America in the middle 1800s.

Hostas in the spring

Depending on which species an individual hosta comes from will determine when it surfaces in the spring. The hereditary genes of the mountain hosta, because it came from a cold region tells it to come up later than the hostas from the warmer lowland areas. The hostas from the mountains were usually found growing on cliffs with water cascading about them all the time. The hostas from the lowlands were found in shade and part shade areas Hostas do not all come up at the same time in the spring. They wait for the soil to warm up and are programmed to come up a little later than other perennials so their emerging leaves will avoid late frosts.

Sun-shade requirements

Some hostas grow best in deep shade. Most grow best in an exposure with some morning sun and afternoon shade. My garden has ideal conditions; the 50 foot high popular trees with no leaves in spring allow lots of sun for the early growth and when the hosta leaves are opening the trees leaves are there to provide shade. The trees shade the hostas from the sun but do not overhang the plants so there is lots of daylight and air circulation.

Hosta colours

Hosta leaves may be a solid colour such as blue, green, gold, or yellow. The blue colour is actually a green leaf coated with a wax that makes it appear blue; the wax will "melt" if exposed to too much sun and the hosta will appear more green. The waxy blue colour usually disappears or wears off by late summer because of heavy watering, sun exposure or just general weathering. There are some hostas that show seasonal foliar changes. Yellow changes to green or visa versa. Variegated hostas of all combinations are very popular.

Watering

Hostas love water and is important for optimal growth. A minimum of an inch of water each week is recommended, and can come from rain, irrigation or hand watering. Hostas in sandy soil may need more water because of increased drainage. In general the greatest growth occurs when water exceeds the minimum recommended rate. Watering hostas on a regular basis early in the day is highly recommended. If hostas suffer from drought they will not grow as large as they should and the affects can even be seen the following year.

Fertilizer

Hostas do best in a well drained garden with lots of compost and rich soil. There are several choices of fertilizer, including liquid, granular and extended release granular. Be careful not to apply fertilizer on top of or on the new growth, eyes or leaves of the plant. A balanced granular fertilizer such as 10-10-10 or 5-10-5 can be applied early in the spring, followed by an application six weeks later, followed by a midsummer application. Read the instructions for application rates.

Propagation and division

Hostas do not come true when started from seed. They can be divided anytime but the best time is early in the spring when the shoots are emerging from the soil. Dig up the entire clump, wash off the excess earth from the roots and using a sharp heavy knife cut between the shoots to divide. You can either cut in half or take off single shoots with roots attached. If you need to divide later in the season dig up the clump, just before dark is best, cut off the leaves to 6 inches from the bottom and divide. Always make sure your newly planted hostas get proper watering. Divide hostas only if you want more hostas. If you think your hosta is too big it is because you have not allowed enough room for growth. When you divide a hosta you lose its maturity so be prepared to wait for full growth potential again. Dividing and using the same variety of hosta is good for mass plantings but to divide the same variety of hosta just to fill a garden is losing the excitement and wonderful diversity of size and colour that hostas produce. Until you've seen a hosta garden with 100-200 different varieties of hostas you will not fully understand the addictive world- wide love that people have for hostas.

Growing hostas in the sun

The hosta species originally grew in cool, wet areas but when they migrated to other parts of the world, these conditions did not always exist and hence shade became a good substitute. Hostas expire a lot of water via their leaves. The hot afternoon sun will tax their ability to supply sufficient water to the leaf. Heat deteriorates the hosta leaf from the edges inwards. Fragrant hostas require more sun to bloom well and can tolerate an excessive amount of afternoon sun. Here are some tips for growing hostas in full sun. Some are more light tolerant than others, see our hosta list for sun tolerant hostas. Hostas with thin leaves do not do well in the sun; thick-leafed hostas or hostas with a heavy substance are better choices. Blue hostas will grow well in sun but tend to lose their blue sheen. When you move hostas from a shady area like the nursery or shade garden to a sunny location they will experience burning for the first year. With age the hosta develops a light tolerance. Mulching under the hosta will substantially reduce soil moisture lose by evaporation. Try to create some shade from the afternoon sun by using tall perennials or shrubs. Avoid planting hostas where the glare from water, windows, rocks or bricks will unnecessarily heat up the hosta. Watering is the most important factor in successfully growing hostas in the sun. Try to avoid over-watering the leaves; make sure the water gets into the roots. Water deeply as a superficial watering is not beneficial to the hosta. Once a hosta matures in full sun it produces many leaves. For May and June my sun hostas suffer almost no burning and look great. When the heat of July arrives some of the leaves start to experience burning around the edges of some leaves; I then pick off the burnt leaves and the plant looks clean again. Full sun will also change the natural colour of the leaf, either turning a yellow leaf more yellow (good), or changing a blue leaf to a greenish-yellow colour (not so good but still a very attractive specimen plant). Some hostas actually look better in sun.

Hostas in containers

Hostas look wonderful in large containers and are very versatile. The pots can be placed on the deck, patio, around the pool, along a walkway or in the garden with the rest of your plants. They also can be strategically placed around the yard taking advantage of any shade if you lack garden space. They only need regular watering once or twice a week depending on weather and some fertilizing. To winter over the container hostas ensure they have a good watering in late fall and then at the end of October tip them on their side in the garden. This prevents the water and ice buildup over winter that can be fatal. Another winter-over method is to take the hosta out of the pot in late October and heal it in anywhere in your garden. Hostas in containers need to be repotted with fresh soil each spring. Do not winter-over hostas or any plants in ceramic containers as the container will crack.

Streaked hostas

Streaked hostas have unstable colouration. Each leaf on a plant will be different. Streaked hostas are very unstable and can try to revert back to an all, one colour hosta. I recommend that if leaves do this you dig up the clump and cut out the offending leaf with its root.

Slugs and snails

Slugs and snails are nocturnal foragers and are the cause of the holes in leaves. By beginning a program of slug-bait application in the spring slugs can be controlled. A granular fertilizer, such as 14-14-14, should be spread around the hostas in early and late spring. The ring of fertilizer will act as a barrier to slugs and fertilize your plants. When the slugs crawl through the fertilizer, the salt (in the fertilizer) will kill them. Be careful not to put fertilizer on the leaves. Apply even if you don't see slug damage as the program will control the population. I also recommend Safers Slug and Snail Bait which is non-toxic to animals. It is a granular product that is spread by hand under and around the plant. Other methods of control, such as beer traps, have limited success. Slugs will eat all hostas so there is no such thing as a "Slug Resistant" hosta. They attack the thin leaved hostas first and the thick leaved hostas last. One can say that if a thick leaved hosta hasn't been eaten in a particular year then it is slug resistant, but it only means your slug population isn't large enough to get to it yet. 

Another slug control method is the spraying of a mixture of ammonia and water directly onto the slugs. I use a mixture of 1 part ammonia and 9 parts water in a small spray bottle. This spray solution only works when sprayed directly onto the slug. (Ammonia is a naturally occurring compound containing nitrogen and hydrogen (NH3) so the plants love it.)