Cultivation Of Hostas
In order to grow superior quality hostas it is essential to do some research regarding their requirements and then provide the plants with the same. Generally speaking, the hostas require rich, fertile soils that are comparatively heavy. In addition, they prefer soils that are somewhat acidic and not neutral. They also grow well in places having a little shade as well as protection from wind. However, if you want to get most excellent results from a wide variety of hostas it is important to understand the individual needs of the plants because hostas surprisingly come from an assortment of environments and many varieties are more demanding compared to what is commonly predictable.
Nearly all varieties of hostas grow excellently in fertile, friable (crumbly) soils having a pH of roughly 6. While these plants will grow excellently in alkaline soils, they do not seem to be happy or healthy when grown on superficial, chalky soils that have a tendency to make the leaves display chlorotic patches. In addition, the glaucous (bluish-green or greenish-blue) leaves develop a muddy shade. In fact, the ideal soil for growing hostas ought to be damp, but having an excellent drainage system. Usually, you can achieve this by blending lots of organic materials into the soil when you are planting hostas and subsequently adding additional organic materials, such as mulch, on a regular basis over several years.
Large hosta varieties like H. “Great Expectations” will also grow excellently on intense clay soils, which are somewhat water-tight, but rich in nutrients for the plants. However, the plants may take a longer time to establish themselves when grown on such soils and even take more time to mature. On the other hand, the plants will establish themselves faster provided you mix plenty of coarse grit along with equal amounts of well-rotten manure from farmyards or garden compost into the soil. While doing so you need to ensure that the grit and compost are mixed with the soil on which the hostas are growing as well as a considerable surrounding area with a view to enable the mature plant roots to spread further than the leaf mound of the hostas. Subsequently, you can maintain the quality of the soil by mulching on a regular basis with additional grit as well as organic substances.
If you are growing hostas on sandy soils, you will be faced with somewhat different problems – however, in a way, these problems are similar to those when the plants are grown on heavy clay soils. Usually, hostas develop healthy root systems when grown on sandy soils. However, the plants do this in order to obtain water and nourishments from all over the place. Basically, sandy soils are not fertile and usually the appearance of hostas grown on such soils becomes thin and wretched unless you initiate appropriate measures to address the related issues. Since sandy soils are extremely permeable, they drain away all the nutrients applied to the soil very fast either due to rains or watering. However, the hostas will grow excellently even in such soils provided you add copious amounts of garden compost or farmyard manure to them at the time of planting. In addition, you need to ensure that you mulch the plants regularly during spring as well as autumn using the same substances. Sometimes, it may become essential to provide the plants with added nutrients and also feed them with decomposed foliages, especially during the early summer months and in spring.
However, it is not advisable to treat the smaller hostas like H. “Shining Tot”, H. venusta or H. “Suzuki Thumbnail” in a similar manner. This is because if you mulch these plants, birds will soon scatter the mulching. At the same time, the small hostas may feel suffocated by the coarse materials used for mulching and dumped on their base. Normally, the small hostas are also not sufficiently strong to be able to struggle against the other hostas or the usual flora found along the woodland or perennial borders. You can use bricks, peat blocks, railroad ties or even large decomposing tree trunks to prepare the raised beds. It is important to prepare these beds in shaded locations and this may usually result in developing a moss cover. The moss possibly will grow more vigorously on the beds’ surface and eventually hold back the hostas. However, you may put off this from happening if you apply a feeble ferrous oxide solution.
As far as the issue of flourishing or languishing is concerned, the quality of preparing the planting site is the single most important factor that usually affects hostas, or for that matter any other plant. There is no doubt that the size of the plant hole will solely depend on the size to which any plant will eventually grow up to. If you are growing large hosta varieties like H. fluctuans “Sagae”, H. Montana and/ or its various forms, H. sieboldiana and/ or any of its forms, you should ensure that the planting hole is big enough for a shrub to grow well. Ideally, you should dig a hole measuring 91 cm (3 feet) across and 45 cm (1.5 feet) deep. At the same time, you need to ensure that the soil at the base of the planting hole is broken up. Fill the bottom half of the planting hole with alternating layers (each measuring 7.5 cm or 3 inches) of garden compost, properly decomposed farm manure and soil. In case the soil is heavy, you need to add some grit. Use a friable blend of the same substances to fill each layer of the upper half of the plant hole. After you have filled the final top layer of the planting hole, ensure to tread it firmly with the heel.
It would be perfect if you prepare the planting holes about one month or even before the planting because the level of freshly worked soil has a tendency to drop somewhat. If you intend to grow smaller hosta varieties, you need to prepare appropriately smaller planting holes. However, in any case, even these planting holes should never be under 45 cm (18 inches) in diameter and 23 cm (9 inches) in depth. On the other hand, supplying appropriate growing medium for dwarf hostas is more vital compared to the size or method of preparing the planting hole.
There are two seasons when you can plant hostas. You may choose to plant them during the spring soon after the shoots come out, as this helps the plants to establish themselves faster while the soil becomes gradually warm. Alternatively, you may also opt to plant hostas during the end of summer or beginning of autumn when the soil still remains warm from the heat of the summer. This warmth also helps the plant to become established quite rapidly. If needed, you may also move the plants during the height of summer when the hostas are in full leaf, provided you cut down the leaves and water the plants appropriately and constantly till they become re-established in their new environment. Never ever plant hostas during winter, as the roots of the plants are inactive during this time of the year. Moreover, too much rain or even frosting may damage the roots or cause them to decompose. In fact, planting hostas when they are able to be seen above the ground offers one great advantage – it allows the gardener to place the plants as well as space them appropriately.
If you are planting hostas which have earlier been grown in containers, you will usually notice that the roots get entangled at the base of the pots. You should try to avoid teasing such roots prior to planting – in fact, even if much of the compost in which the plant has been growing thus far is lost, don’t consider it to be a disaster. On the other hand, if you are planting hostas that have been growing in an open ground, it would be wise as well as good for the plants if you get rid of the old soil to enable the roots to grow afresh in the new soil. Also get rid of all damaged or dead roots using pruning shears (secateurs) or a sharp knife. When you have placed the hosta in its planting hole, replace the soil in different layers. It is advisable that you firm up each layer before you add another.
After you have planted the hosta in its hole, ensure that you water the plant properly; especial attention should be given on watering the plant during the subsequent months. This is all the more true if you are planting the hosta in spring. After soaking the roots of the hosta initially, it is more effectual to slowly trickle water into the ground surrounding the plant by using a hose compared to sporadic sloughing with water. Subsequent to this, it is essential to ensure that the ground around the plant always remains moist. It is worth mentioning here that if you are growing large varieties of hostas you require providing them with no less than 4.5 litres water daily till the plants are established properly. In addition, it would be beneficial for the plants if you subsequently place a substantial cover of organic mulching substances much in the shape of a doughnut ring around the hostas.
Mulching and feeding
Generally, hostas are considered to be gross feeders. However, this only holds true for the larger hosta varieties. For hosta varieties that are smaller compared to H. sieboldii, it is more essential to provide the plants with appropriate growing medium plus sufficient watering. Nearly all types of hostas are very receptive to applying liberal amounts of fertilizers and manures.
In fact, organic feeds like garden compost, farmyard manure or leaf-mould are more valuable for hostas compared to the chemical fertilizers. However, the fact is that the organic materials often contain disappointing levels of nutrition, which are also usually not present in balanced amounts. The nutritional levels of the organic substances differ from one batch to another. In addition, usually these types of organic materials also contain lots of weeds.
However, humus contained by these organic materials is very useful for hostas, as it helps in their growth. In addition, humus also facilitates in maintaining a balanced moisture level in the soil, besides being excellent carriers for various other nutrients. On the other hand, the nutritional levels of all artificial fertilizers, as well as nearly all packaged plant foods, irrespective of them being powdered or pellets, is known and they offer the gardener an opportunity to select the fertilizer that he wants to feed the plants. For instance, a gardener may choose to apply a high potash feed or a high nitrogen feed to his favourite plants.
It has been found that hostas have a huge demand for nitrogen available in the soil and unless the supplies are sufficient, it will not quench their enormous appetite for the nutrient, which helps them to prepare their own food in the presence of sunlight. This is particularly true in the case of hosta varieties having larger leaves. Although majority of the organic mulches may provide the plants with some amount of nitrogen in the longer run, but they usually result in temporary nitrogen deficits. In effect, the mulch contains the crucial organisms that are drawn from the soil and help to convert nitrogen. These organisms have a vital role in breaking down the nitrogen absorbed from the atmosphere. This is the main reason why you should always use fertilizers with high nitrogen content when you apply mulch. This is particularly vital during the spring. In fact, providing hostas with adequate nitrogen is crucial during spring, when the growth of the plants is optimum. Therefore it may be necessary to apply quick-acting fertilizers with elevated nitrogen content like pelleted chicken manure or dried blood to ensure the healthy growth of the plants.
Nevertheless you need to avoid applying too much or unbalanced high-nitrogen fertilizers, as it will have a tendency to stimulate hostas to produce verdant, and soft foliage. This foliage is very resilient to wind and changing weather conditions, which can damage the plants easily. The downside of this is that snails and slugs enjoy this type of foliage very much. In order to avoid this from occurring you need to always balance the nitrogen by adding potash (potassium), which helps the plants to produce dense and crisp leaves. Hostas also require phosphorous for excellent root development and, therefore, it is advisable that you provide the plants with a well balanced feed. Fertilizers contain a wide range of elements and they are expressed as P for potash, N for nitrogen and K for phosphorus. If it is a high-nitrogen fertilizer, the nitrogen content of it will usually be double that of potassium and phosphorus, while these elements will be present in equal proportions in a balanced fertilizer. Nearly all varieties of fertilizers also enclose small amounts of trace elements, which are also extremely necessary for the healthy growth of the plants.
You may apply powdered or pellet fertilizers by scattering them in the form of a ring surrounding the roots of hostas. Alternatively, you may also provide them with foliar feed, which can be applied using a dilutor connected to a hose or a can. In fact, foliar feed is especially suitable for hostas, as the plants like the additional water that is provided by foliar feed. In addition, foliar feed also makes the leaves of the plants dark as well as glossy.
It is essential to provide hostas with necessary nutriments via fertilizers and manures during the period between the start of spring and mid-summer. If you apply any feed, despite being a balanced feed, after this period will encourage soft and sappy growth of the plants making them susceptible to diseases as well as snails and slugs.
You will notice that the leaves of growing hostas will continue to be swollen or distended owing to the water pressure inside them. In fact, this occurs as the leaves’ surface releases water vapour, thereby creating a limited void, which, in turn, draws additional water into the plant by means of its roots with a view to replenish the water that has been lost due to evaporation. This process continues as long as there is daylight and it helps to keep the leaves distended and turgid. Simply speaking, any hosta plant having big leaves similar to the leaves of H. “Sum and Substance” or H. “Snowden” usually releases plenty of water vapour from its leaves and, therefore, needs to suck much water via its roots to keep this process going on. In fact, the leaf size of the hostas is completely subject to their getting sufficient moisture, which actually helps to heighten their suckering effect. In case sufficient water is not available to the leaves, for instance in an arid region, during droughts, or when the leaves have been harvested, the leaves no longer remain turgid. Instead, they turn out to be limp and eventually wither away. This is the main reason why it is necessary to water the hostas, especially to ensure that they succeed and thrive well in all conditions.
You may normally assume that the best means to water hostas is use any means that has a close resemblance to rain. However, in reality, this is never the most favourable means to water these plants. There is a problem if you water the hostas in a way akin to the rain. In this case, the water droplets that fall continuously on the blue-leaved hosta’s leaves can actually spoil the glaucous (bluish-green) bloom for which these hostas are valued most. However, using fine mist sprays helps to put off this problem. There is yet another problem when you water the plants from overhead. In case you apply water from the top and the leaves of the plants are exposed to sunlight, the droplets are likely to divert the sun rays to focus on the leaf surface, thereby burning it or disfiguring the leaf and causing yellow stains on the leaf.
Therefore, the most effectual means to water hostas is applying water directly to the roots of the plants by using a hose or can. In case you are cultivating hostas extensively, you may water the plants using a seep hose. While watering hostas, your aim should be to maintain even moisture in the soil around them and also to prevent sporadic extremes of aridness and wetness.
At the same time, you should ensure that watering of hostas should be undertaken very early in the morning, prior to the sun’s rays turning hot. In this case, the hostas can use the water throughout the day – this is important as the hostas or for that matter any plant can make use of water only in the presence of sunlight. You will have to face a number of problems if you water the plants during the evening, for instance the moisture will have a propensity to attract snails and slugs, which are fond of damp environments. As far as watering of hostas is concerned, you should follow the same principles for the plants grown in tubs and pots. In fact, potted plants are more susceptible of desiccating compared to the hostas that are cultivated in the ground.
Often, it is believed that hostas have a preference for shade. Although this is true for numerous hostas varieties, it is essentially the rule of thumb. Considering the fact that hostas require sufficient moisture, for instance H. “On Stage”, whose leaves have plenty of yellow pigment and very little green, have better colors when they are grown directly under sunlight. On the other hand, there are several instances of hostas having better leaves when grown in the shade, but produce better flowers when grown in sunlight.
Hostas growing in the wild actually grow in a wide range of conditions that provide them with adequate shade. While some hosta varieties grow in open cryptomeria or coniferous forests, there are other varieties like H. longissima, which are found growing in high-altitude water fields where the plants receive shade cast by the taller grasses (often miscanthus). There are other varieties that are found growing on mountains, where the plants are covered by cloud nearly all the times. A few hostas varieties are also found growing either in crevices along the mountain stream or rocks where the plants always avail water. In such cases, the requirement for shade is adequately balanced by the abundance availability of water. Nevertheless, it is not easy to reproduce these conditions easily in the Western gardens. This is the main reason why most gardeners grow hostas in shaded locations.
When we talk about shade, we just do not mean the non-existence of direct sunlight. In effect, this can be achieved by modifying the microclimate, getting cooler and damper air, usually preserving the additional moisture of the soil in case a lot of competing tree roots is present in the neighbourhood.
It has been found that the growth of hostas is most excellent in light, spotted shade – for instance the type of shade that is cast by the canopy of taller trees. However, there is one problem – when the trees are young they cast too little shade, while they cast too much shade when they become mature. On the other hand, an appropriate amount of shade can be created more easily by means of artificial methods. For instance, building a pergola will provide the hostas with the right amount of shade.
Usually, most gardeners have to be satisfied with the shade available in their gardens. However, if there is prospect of creating a diverse range of shade density for the hostas by using trees, it is preferable to use three trees instead of one. Provided you plant the trees in the form of an equilateral triangle and their hypoteneuse forms a line passing from east to west and their tips lying towards the north of this line (in the case of growing them in the northern hemisphere), you will find that the planting triangle will receive the highest density of shade. The region in the southern end of the hypoteneuse will receive total sunlight, but the shade will be lighter in the areas that are in the north-east and the north-west side of the triangle for nearly half of the daytime.
It may seem that trees will offer an graceful and apparently natural surrounding for the hostas, but you ought to remember that they will also be competing for the same nutrients and moisture, therefore making it more important to provide the hostas with additional and proper nourishments and water. Moreover, there will be some trees in the garden that will contend with the hostas more openly compared to the others. For instance, birches and cherries are surface-rooting and they will definitely overrun the space when the roots of the hostas should be. This will deprive the hostas of the much-needed space. In addition, beeches as well as majority of the maples also have roots that come up on the surface of the soil. On the other hand, some trees, such as catalpas, which produce leaves at a very late stage, will let the hostas grow faster below, prior to the appearance of their leaves that provide a protective shade to the hostas.
Hostas growing in appropriate environments usually have a luxurious and nourished appearance. However, occasionally hostas appear to be absolutely miserable and they do not have normally large leaves. In addition, the plants are not as expanded as they normally ought to be. Sometimes, they are also somewhat limp. Most often lack of proper nourishment or watering is responsible for such condition of the plants, but the absence of shelter. In the lack of appropriate shelter or protection, hostas leaves are open to very strong or excessive wind, which spoils the leaves owing to its utter force often bruising and knocking them. Moreover, wind dries out the leaves and, in worst conditions, even scorches them.
In fact, wind that blows across the leaves desiccates them in the same way as it dries out laundry on the line. As a result of this, the roots of the plants come under tremendous pressure, as they need to supply additional water to maintain the turgidity of the leaves. In a number of conditions, it may not be possible for the roots to provide the leaves with more water, thereby making the leaves appear worn-out and withered.
It is important to bear in mind that you should never grow hostas in places that are exposed to winds. In case you have no alternative but to grow them in such places, you should ensure that there is additional protection to the plants to reduce the power of the wind. Eventually, this may mean that you have to grow hedges or a series of shrubs or trees to protect the hostas. However, provisionally you may also erect fences to lessen or divert the power of the winds. Alternatively, you may also use the contemporary flexible plastic materials that serve as wind breakers. The advantage of using these contemporary materials is that similar to hedges and some type of fencings, which are semi-permeable, they are also effective in reducing the force of winds instead of causing the wind to blow up and over. When the wind is forced to go up and over the plants it generally results in instability, which can be equally harmful as the winds blowing through the plants.
The anatomy of hostas
Propagation of hostas
Growing hostas in containers
Hostas in the garden
Pest and diseases of hostas
Companion shade plants for hostas
- From Al Miller, West Chester, OH – Feb-18-2011
- Enjoying many varieties of hosta and over 1000 plants in all, I find the article above to be quite accurate and informative. Large planting holes with lots of added compost and a slow-release well-balanced fertilizer added twice a year will provide the perfect home for most hosta plants. Watering is our prime concern in the hotter months of the year as the adjacent trees seem to consume most of what nature provides.