WHAT IS WASABI?

wasabi root and leaf on wooden table
What is wasabi?


Commonly known as the Japanese horseradish, the wasabi plant - Wasabia japonica is an edible herbaceous perennial whose natural habitat is found partially submerged along mountain stream beds in Japan. Despite certain similarities the wasabi plant isn't a close relation to the European horseradish - Armoracia rusticana, syn. Cochlearia armoracia, although they are both genera of the Brassicaceae family. Conversely, in Japan the horseradish is known as European wasabi!

Wasabi growing by a pond
Wasabi in ts native habitat
The mature wasabi plant produces large heart shaped leaves, which protrude from the top of a swollen rhizome-like stem, holding the leaves as high as 60 cm above ground at the base of the plant. The true roots are usually submerged and firmly anchor the plant to prevent it being washed away during floods. The plant takes two years to reach maturity requiring mild temperatures and filtered sunlight.

Wasabi has been apart of Japanese cuisine for thousands of years, in fact archaeological evidence has shown that the ancient Japanese were eating wasabi as early as 14,000 B.C. Although rare to find and notoriously difficult to bring under cultivation, the use of wasabi was widespread by the 16th century but the cost of production restricted its use to the Japanese ruling class. Be that as it may, the production both improved and increased with the rise in popularity of sushi, when wasabi became the preferred flavouring. In sushi preparation, the wasabi is usually placed between the fish and the rice because covering wasabi until served preserves its flavor. Wasabi was also prized for its ability to counteract food poisoning.

wasabi stem being grated
Preparing wasabi
When preparing fresh wasabi, remove the leaves and then rinse the stem under cold running water. It is not necessary to peel the stem, but any dark patches of skin can be removed for a uniformly coloured paste. The greenest, sweetest wasabi will be at the foliage end of the stem and this is where you should start to grate. Using a wasabi grater (known as an oroshigane), grate in a circular motion to produce a fine paste. Only grate what you need as it will lose its flavour after 15 minutes or so. You can always grate more if you need it later.

Using a wasabi brush that should have been purchased with the grate, remove the wasabi onto a wooden or ceramic surface as the steel surface of the grate will speed up the oxidation process and affect the flavour. Wasabi loses its flavour after 15-20 minutes when exposed to air so gather the paste into a ball as this minimizes contact with the air and prolongs the flavour. Let it rest at room temperature for up to 5 minutes to allow the flavours to develop, then it’s ready to serve. You can improve the flavour of an older wasabi ball by grating a little fresh wasabi onto the pile and gathering it up into a ball again.

Although eaten in very small amounts, you may be interested to know that wasabi is very low in cholesterol and sodium and is a source of dietary fibre and vitamin C. Wasabi is also a good source of Vitamin B6, calcium, magnesium, potassium and manganese.

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HOW TO OVERWINTER TREE FERNS

tree fern forest
How to overwinter tree ferns


Tree ferns are among some of the world's great architectural garden plants, and while they are native across the tropical and subtropical areas regions of South Africa, Australia, Tasmania, New Guinea and New Zealand there are a number of the thousand or so species which are hardy enough to survive planted outside in northern European countries. In fact in the milder regions of southwest England there are areas where species such as Dicksonia antarctica have been left to their to their own devices quite successfully for almost a century.

Of course, shipping tree fern trunks halfway across the world can make them an expensive purchase so to ensure that your prized specimen survives year after year it is prudent to put in place suitable cold protection so that they can survive our freezing winters relatively unscathed.

Tree ferns with winter protection of straw
How to overwinter tree ferns
The new growth of tree ferns is produced at its crown, although side crowns can occur on mature specimens. While thick taproots run from the crown down through the trunk and into the soil the thick fibrous qualities of the trunk is usually enough to provide adequate cold protection for this specialist above-ground root system.

The crown of the tree fern is another matter and will require cold protection, especially the further north they are planted. The old brown, dried fronds can be packed into the crown, alternatively use bracken or straw. Do not push your protective material to hard into the crown as this can cause damage to the tightly wound 'embryonic' fronds known as crosiers. This level of protection will be perfectly adequate for the south of England and should be put in place before the first hard frosts - usually october to November.

Further north and the longer freezing temperatures will require an upgrade in cold protection. Gather the fronds around the crown and tie them up. Wrap the entire plant in layers of frost protection fleece. The colder the temperature the more layers will be required.

For less hardy specimens such as Dicksonia squarrosa, Dicksonia fibrosa and Cyathea dealbata pack the fleece with a thick layer of straw or bracken.

Take off the protective fleece in the spring, and remove the crown protection before the new fronds come into growth. Container grown plants in milder areas should be placed under protection in a sheltered frost-free position with the container bubble-wrapped to prevent the roots from becoming cold damaged. Countries with a more arctic winter such as Canada, or Scotland tree ferns are best lifted and brought into a frost-free conservatory or greenhouse.

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HOW TO OVERWINTER GUNNERA MANICATA



The giant ornamental rhubarb - Gunnera manicata is a near-hardy perennial native to South America from Colombia to Brazil. It will grow best in damp conditions such as the side of a natural ponds, but when grown in the colder regions of northern Europe the crown and near-surface roots can suffer damage under extended periods of freezing, wet conditions.

Gunnera manicata crown covered by old leaves
How to overwinter Gunnera manicata
Traditionally, the crown is protected by covering it with its own leaves either weighed down with soil or secured in place using small branches or its own leaf-stems. This procedure is usually undertaken after the first light frosts in October. As soon as the leaves begin to show the effects of cold damage they can be removed but if the weather's still warm then delay cutting as the heat will cause warm, humid conditions around the crown which can encourage fungal infections to take hold.

Be aware that the stems and undersides of Gunnera leaves are covered in thick spines so unless you have the gnarled hands of a northern bricklayer you should wear thick, protective gloves. While the spines are not sharp enough to puncture the skin, they are quite capable of inflicting deep and painful scratches.

First remove the leaves by cutting the stems near the crown using a sharp blade or silky saw. Then remove the stems by cutting them away from the base of the leaf. Any flower or seed stalks can also be removed and placed around the crown for extra protection. First, cover the top of the crown with 2 or three leaves, then place the remaining leaves in a cone shape around the crown. The leaf-stems can now be place on top of the leaves to help keep them in place.

Young plants may not have produced enough leaves during the growing season to provide itself with enough protection. In this instance provide a thick mulch of straw instead and cover that with whatever leaves are available.

In the spring the leaves and soil can be drawn aside to expose the crown, but left in place to act as a mulch.

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HOW TO OVERWINTER CANNA LILIES

canna flower yellow and red
How to overwinter Canna lilies


Canna lilies are a spectacular, late summer flowering perennial, and a popular choice in northern Europe for those who wants to bring a taste of the exotic into the garden. Furthermore, if you are lucky with the weather then you can experience these gorgeous blooms right up to the beginning of December!

overwintered canna stems
How to overwinter Canna lilies
Although Canna lilies originate in the tropics, some of the most ornamental cultivated varieties have been produced in cooler temperate regions, but in areas which receive freezing temperatures they are unlikely to survive and often treated as an annual. However in the warmer parts of northern Europe, such as the southwest coast of England, it is possible to leave your Cannas outside all year round so long as they are planted a little deeper than recommended and in a free draining soil. If your garden has heavier, poorer draining soils the consider planting canna lilies into raised beds.

To reduce the penetration of ground frosts the apply a thick layer of dry mulch such as straw, bracken or bark chips. Be aware that successfully overwintered canna lilies will emerge much later than specimens lifted and brought in under protection. In fact you may not see your first leaves emerge until late June, or even early July!

Traditional overwintering of Canna lilies

rooted canna stems
How to overwinter Canna lilies
Canna lilies can be lifted as soon as the top growth begins to wither which is usually after the first light frost. Carefully lift them out of the ground (trying to keep the root system as intact and 'undisturbed' as possible) and allow the plants to partially dry off in the late autumn sun. If rain is forecast then bring them under cover.

Before the plants become too dry, cut off the leaves and roots in readiness for storing through the winter. Plant up the rooted stems in moist, but not wet, peat or leaf mold in a frost-free position. If kept too dry the rhizomes will shrivel up and die, but keep them too wet and they will be at risk of rotting off during to fungal infections.

Overwintered canna lilies can be planted back outside in late spring once the threat of late frosts have passed.

NOTE. If you know that you will be lifting your canna lilies at the time of purchase then consider planting into large terracotta pots beforehand and sinking those into the ground. This makes lifting them later on on the season a much simpler operation.

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WHAT IS A DRY MULCH?

A bag of bark chips sitting on a  bed of bark chips
What is a dry mulch?


All gardeners will be familiar with mulching their plants. A healthy dose of nutritious, rich compost is just the thing for many species as it can provide a whole growing seasons worth of natural, slow release fertilizer.

Landscaped garden with gravel and bark chip dry mulches
Landscaped garden with gravel and bark chip dry mulches
Of course a mulch will do more than just supply food for plants. They can help to retain moisture in in the soil, and suppress the growth of completing weeds. This type of organic mulch has different purpose to a dry mulch and as such is loosely listed as a 'biodegradable mulch' although a dry mulch can also be biodegradable and may require several applications.

When using organic mulches avoid direct contact with the stems of trees or specimen shrubs as this can cause the trunk or stem to soften, making them vulnerable to diseases.

A dry mulch is primarily used for protecting susceptible plant roots from extremes of temperature and to reduce the incidence of fungal roots that could be encouraged when a regular mulch bio-degrades. They are usually applied in late autumn as a cold protection for plants whose roots are at risk of damage from ground frosts.

Dry mulch around the bases of trees and shrubs
Dry mulch around the bases of trees and shrubs
Traditionally, bracken fronds, pine needles, shredded leaves and straw are used as dry mulches, but as these degrade in the cold wet weather they would need subsequent applications to maintain a reasonable level of protection.

Gravels may also be applied in appropriate borders but perhaps the most commonly used dry mulch used today is bark chips. Dry mulches are usually removed in the spring to allow the soil to warm faster. Be aware though that when using wood chips there is a slight risk of introducing honey fungus

Dry mulches can also just be used for decorative effect with no intended benefit to the plants themselves except to serve as an ornamental background. In this instance, many materials can be used to achieve this including slates, pebbles, stone chippings, crushed CDs, sea shells, and tumbled glass.

For decorative mulches a woven landscape fabric should be laid down before their application.

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HOW TO GROW CUP AND SAUCER' PLANT FROM SEED - Cobaea scandens

The 'Cup and Saucer' plant in flower
The 'Cup and Saucer' plant - Cobaea scandens


The 'Cup and Saucer' plant - Cobaea scandens, is a stunning half-hardy perennial climber native to tropical Mexico.

The 'Cup and Saucer' plant seeds - Cobaea scandens
The 'Cup and Saucer' plant seeds - Cobaea scandens
In northern Europe it can be grown as a perennial in a cool greenhouse or conservatory, but is usually grown outside as an annual on a south facing wall. It is a vigorous climber that is noted for its large purple, bell-shaped corolla which is embraced by a green saucer-like calix - hence its common name.

To make the most of the growing season Cobaea scandens seeds are sown in February or March. Before sowing soak the seed for 2 hours in lukewarm water before sowing. To maintain the temperature place the seeds and water inside a thermos flask.

Using a modular seed tray, fill with a good quality peat-based compost and gently water in. Allow the excess water to drain off and then press one seed into the surface of the compost at a rate of one seed per module. Do not cover the seed as it requires the presence of light to help initiate germination.

Place the tray inside a heated propagator at a temperature of between 18-24C and place on a warm bright windowsill, but out of direct sunlight during the warmest part of the day. Alternatively seal inside a clear polythene bag after sowing is helpful. You can expect germination to occur within 21-30 days.

The 'Cup and Saucer' plant seeds - Cobaea scandens
Image credit - http://davesgarden.com/
Once the root systems have established inside the module, carefully pop them out trying to disturb the root system as little as possible. Pot them on into 5 inch pots using a multi-purpose compost and grow on in cooler conditions. Keeping them well watered and once the threat of late frosts have passed they can be gradually acclimatise to outdoor conditions for 10-15 days before planting out into their final positions.

after all risk of frost 60 cm (24 in) apart in a sheltered spot in sun on ordinary well drained soil. For summer flowering under glass, transplant into 20-23 cm (8-9 in) pots, and keep the atmosphere fairly humid.

The 'Cup and Saucer' plant will do best in a sunny, sheltered position in ordinary well-drained soil. Avoid the temptation of adding fertilizer to the soil beforehand as this can reduce the number of blooms.

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HOW TO GROW ALSTROEMERIA FROM SEED

Yellow Alstroemeria in flower
How to grow Alstroemeria from seed




Alstroemeria are undoubtedly one of the most ornamental of all late summer flowering plants however they are comparatively expensive to other herbaceous plants and almost always only available as pot grown stock. Be that as it may, Alstroemeria are relatively easy to grow from seed and if you can't find any to purchase in your local garden stores then you can always collect your own seed from established plants. Be aware though that you will need to break seed dormancy first, and even then viability of the seed will vary.

Alstroemeria seed pod
Alstroemeria seed pod
Under normal cultivation old flowering stems are cut back to near ground level in late autumn or early winter, but these stems will need to be left in place if you want to collect the seed later on.

You can sow Alstroemeria seed any time from mid winter to mid spring. Fill a modula seed (with approximately 1 inch sq modules) with a moist, soil-less and well drained potting compost. You may need to mix in some horticultural grit to improve the drainage further. John Innes compost will not be suitable for this. Make sure that the compost is only ever kept moist and never waterlogged during the germination period otherwise the seeds can rot.

Sow two seeds in each module at a depth of ¼ inch. Gently water in and once the excess water has drained off place the tray inside a heated propagator at a temperature 21 degrees Celsius.

Alstroemeria seedlings
Alstroemeria seedlings
After three weeks remove the tray from propagator. Water again if necessary and then seal the tray inside a clear polythene bag. Now place the tray inside the main compartment of a refrigerator for the next three weeks. Just check the temperature to make sure that it is set at 5 degrees Celsius.

Once this cool period is over return the tray to the heated propagator, again at 21 degrees Celsius. You can expect your Alstroemeria seedlings to emerge in 10 to 14 days. Remove the tray from the propagator as soon as the first seedlings appear as the high humidity can cause fungal rots to take hold.

Once the root system of seedlings have become established in their modules carefully pop them out so as to disturb the root system as little as possible. Pot them into 3-4 inch pots using a good quality multi-purpose compost and grow them on in bright, frost-free conditions. Once the threat of late frosts have passed they can be hardened off and planted outside in a sheltered position into well-drained soil.

Main image credit - - By JJ Harrison (https://www.jjharrison.com.au/) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=5504703

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HOW TO GROW HYACINTH BULBS

Field grown hyacinth bulbs in mixed blooms
How to grow Hyacinth bulbs

As a true species, the common hyacinth - Hyacinthus orientalis is rarely (if ever) grown under commercial production. However the huge number of extremely popular Dutch cultivars and hybrids make it one of the most commercially successful of all bulbs.

Native to eastern Europe and west Asia, the common hyacinth will produce an extremely colourful flower spike between 4 and 12 inches tall depending upon the variety. Often sold as forced hyacinths, skilled production and special storage conditions enable most forms to flower before Christmas. When left to their own devices you would normally expect hyacinths to flower between February and May depending on environmental conditions and the initiation requirement of the individual cultivar.

Forced hyacinths would need to be potted up in August or September using either bulb fibre or a good quality compost such as John Innes 'No 2' to ensure their flowering before Christmas. Untreated bulbs will of course flower later and can be potted in succession from August to October.

Blue hyacinth in flower
How to grow Hyacinth bulbs
Be aware that bulb fibre provides bulbs with little (if any) nutrients and so bulbs grown in it as a rooting medium can exhaust their energy supplies through flowering. Subsequently if they are planted in the garden it may be a couple of years before they flower again. This is not the case of bulbs planted in regular compost.

After flowering, forced hyacinths can be planted 6 inches deep outside into their final position in March and April. They will do best in well-drained, moderately fertile soil, in a sunny position.

Keep the surrounding area free of weeds and and remove any dead leaves or flower stalks as they arise. Avoid watering over the summer and once the bulb comes into leaf feed regularly with a good quality, liquid soluble fertiliser. If left undisturbed they will continue to flower year after year.

For spring bedding displays plant hyacinth bulbs 5-6 inches deep in the autumn after the summer bedding has been removed. Hyacinth bulbs will not do well when competing with other plants, so in order to guarantee a good display year after year he bulbs should be planted at least 6 inches away from other plants. If this is not practical then they can always be lifted after flowering and replanted in a more suitable position.

Main image credit - John O'Neill Hyacinths - floriade canberra CC BY-SA 3.0
In text image - By The wub - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20184777

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HOW TO GROW THE SHRIMP PLANT

shrimp plant flower
How to grow the shrimp plant


The Mexican Shrimp Plant - Justicia brandegeana is a gorgeous ornamental flowering plant from the subtropical forests of Mexico. Seen only as a houseplant in northern Europe it also makes for an excellent summer bedding plant, but in warmer temperate or subtropical regions it is a fantastic evergreen shrub for those hard to plant shady positions.

The shrimp plant as a houseplant

Justicia brandegeana - botanical drawing
Justicia brandegeana - botanical drawing
As houseplants go the shrimp plant is fairly vigorous, growing up to approximately 1 meter in height and 50 centimetres wide. Usually purchased in the spring in 3 inch pots, the shrimp plant can be potted on in March into 5-6 inch pots using a good quality compost such as John Innes 'No 2 or 3'.

Over the summer the plants will need to be kept cool and well-ventilated, but if they are hardened off and kept outside for the summer they will be quite happy in a damp shaded position with high humidity. If kept inside, the high humidity of the kitchen or bathroom will provide suitable conditions but if placed elsewhere an occasional spray with tepid water will do the trick.

Water freely from March to November, but over the winter you will need to reduce watering to keep the compost just on the moist side. Do not allow the roots to become waterlogged over this period as cold, wet conditions can allow your shrimp plant to succumb to fungal root rots. During the growing period apply as liquid soluble fertilizer every week or so, usually from May to September. Do not allow the shrimp plant to experience temperatures below 7 degrees Celsius.

The shrimp plant as a garden plant

When growing the shrimp plant as an evergreen shrub in the garden you will need to site it in a damp. but well-drained position in the shade. It will prefer a sandy, loamy soil and once established is surprisingly drought tolerant. It will not require mulching or applications of liquid fertiliser.

Pruning

Remove the first bracts of young plants to encourage sturdy, free-flowering plants. In February, cut the main stems back lightly to encourage a more compact and ornamental shape.

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HOW TO GROW THE GOLDEN SHRIMP PLANT - Pachystachys lutea

Golden Shrimp plant - Pachystachys lutea in yellow flower
How to grow the Golden Shrimp plant - Pachystachys lutea


The Golden Shrimp plant - Pachystachys lutea is a gorgeous, soft-stemmed evergreen from the subtropical regions of Peru and grown in Europe either as a houseplant or as summer bedding.

It produces, lush, heavily-veined, dark green leaves, but its most ornamental feature is the brightly coloured, thick-stemmed flowering body. The true flowers are the short-lived white blooms which emerge throughout the summer from the overlapping bright golden-yellow bracts.

Golden Shrimp plant - Pachystachys lutea in full bloom
How to grow the Golden Shrimp plant - Pachystachys lutea
The Golden Shrimp plant will grow best in most damp but well-drained soils so long as they are slightly acidic. If your soil is particularly alkaline or chalky then it can be improved by digging in moss peat, or sulphur based products such as Aluminium sulphate (used in hydrangea colourants) and Ferrous sulphate (sulphate of iron). Always use a pH tester to judge your results and note that clay soils have a natural buffering capacity so much more sulphur is needed to change their pH when compared to a sandy soil. For pot grown plants the solution is easy as you would simply use an acidic compost, usually sold as ericaceous compost in garden centres.

As a result of their subtropical origins, the golden shrimp plant will need to be kept in a position that receives as much light as possible, so position garden plants in full sun and house plants near a south facing window. Water frequently over the summer months and regularly mist with tepid water if humidity is low. Pot grown plants will require feeding with a liquid soluble fertiliser every week or so.

The golden shrimp plant will need little maintenance outside, but as they have the capacity to grow anywhere between 1-2 metres in both height and width favourable condition indoors can mean that they will outgrow their allotted space. Luckily, this plant will respond well to pruning, a task that is best carried out in the spring. Always cut back to just above a leaf node and is need be you can remove up to a third of the branches.

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HOW TO GROW ECHINOCACTUS GRUSONII FROM SEED

large ECHINOCACTUS GRUSONII specimens
César Manrique jardin de cactus in Lanzarote


Echinocactus grusonii is a slow growing, globular or cylindrical cacti which given the right environmental conditions can reach up to a metre in height and width. They are cultivated for their beautiful spines, but when grown as houseplants in temperate regions they are the most unlikely to flower of all cacti species.

Native to east-central Mexico, be aware that Echinocactus grusonii will need full sunlight to produce the good spine formation. It is the ornamental effect of the spines that has helped this particular species become one of the more widely cultivated of all cacti.

ECHINOCACTUS GRUSONII SEEDlings in seed tray
Image credit - http://www.cactiguide.com/
When growing in northern Europe, the best germination results are achieved by sowing Echinocactus grusonii seed in April. Using a modular seed tray, fill with a good quality compost, such as John Innes 'Seed and Cutting', with a few handfuls of horticultural grit mixed in to help improve the drainage further. Gently water the compost in then sow one seed per module, gently pressing the seed into the surface of the compost. Be careful not to cover the seed with compost as Echinocactus seed needs the presence of light to help initiate germination. You can however provide a light sprinkling of vermiculite or horticultural grit.

Place the tray inside a heated propagator at a temperature of approximately 21 degrees Celsius, then keep the tray in a warm room that receives as much light as possible although try to avoid direct sunlight during the hottest part of the day. Alternatively seal the tray inside a clear polythene bag.

Field grown Echinocactus grusonii in China
Field grown E. grusonii in China - image credit http://www.ec21.com/
You can expect the seedlings to emerge within 2-3 months, at which point they can be removed from their propagator or polythene bag. Avoid the temptation to water until the first two cotyledons are present, and do not touch them as this can damage their growth.

Pot on as necessary using a good quality, open cactus compost but you can make your own by using 1 part by volume horticultural sand to 2 parts John Innes 'No2' compost. This is only really necessary every 2-3 years and then only on warm sunny days.

Never allow temperatures to drop below 8 degrees Celsius, and while they will tolerate dry conditions an occasional spray of warm, tepid water will do wonders. Water as necessary but avoid watering from above especially on hot sunny days as the plants can easily become scorched. Remember that cacti will carry the scars their existence throughout their life. Over the winter period you can reduce watering to once a month and even then do not allow the compost to become fully soaked.

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