How to control bindweed - Convolvulus arvensis

Closely related to the morning glory family, the field bindweed is a native to Europe and Asia. However, as pretty as its blooms are, the field bindweed is also a pernicious garden weed which if left unmanaged can easily swamp a suburban border and contaminate lawns. It is also notorious for out-competing ornamental species for sunlight, moisture and nutrients and is one of the most serious of agricultural weeds in the temperate regions of the world!

How to control bindweed - Convolvulus arvensis
A single plant can produce up to 500 seeds in a season, with each seed capable of remaining viable in the ground for up to 20 years! However it is arguably the deep, extensive, brittle root system which causes the biggest headaches. Any attempt to hand dig out the field bindweed invariably results in the roots snapping. Even a small section of root can contain sufficient carbohydrates and proteins to allow it to sprout repeatedly following the removal of the above-ground growth.

Organic control of bindweed

It is possible to manage bindweed by persistent digging and hoeing. Over time the plants will weaken and over a couple of years of relentless pursuit it is possible to wear out the root systems. Just remember that dormant seeds will stay viable in the ground for decades and so consider organic control of bindweed as an almost permanent feature .

On allotments, one popular method is to cover the area in old carpet for a year or so as the lack of sunlight to the soils effectively killing off most vegetation.

Chemical control of bindweed

The chemical of choice is Glyphosate. This is a non-selective weed killer which will affect any plant when applied to green growth, so be careful what you spray and avoid windy conditions. The reason why it is the chemical of choice is because it travels throughout the plant's vascular system killing both the top growth foliage and the roots. It also deactivates on contact with soil so that you can replant without the risk of damaging newly planted or sown plants.

In text image credit - Bouba - Convolvulus arvensis, 28 juin 2004, Jardin des Plantes de Paris (fr:Jardin des Plantes de Paris)


Black spots on pansy and viola leaves

Your precious pansies and violas seem to be doing well until one day you notice that the leaves are covered in tiny black spots. The plants appear otherwise healthy and the spots themselves are difficult to see. However once you know they are there the evidence becomes glaring.

The spots can appear as either small, round pin pricks or irregular blotches. These are caused by one, and sometimes more of three specific fungi, namely Ramularia lactea, Ramularia agrestis and Mycocentrospora acerina.

There is some bad news as these fungal spores are only spread by rain over short distances and not wind-borne, so the likely source of the fungus is from the purchase of infected plants.That being said it is possible that wild pansies and violas may also provide sources of infection for garden specimens. To add another layer of bad news non-chemical controls only go as far as to avoid repeat planting on the same site to prevent the build-up of these pathogens in the soil. There is no specific chemical control for black spots on pansy and viola leaves however consider using Bayer Fungus Fighter Concentrate, Bayer Fungus Fighter Plus, Scotts Fungus Clear Ultra and Scotts Fungus Clear Ultra Gun.

These fungal spores develop in humid, moist conditions and so as a precaution, and while it is not always easy always try to water from the base and avoid splashing leaves and flowers.

Be aware that without preventive measures these fungal spores can contaminate the soil for several years.


How to grow Prunus shirotae

Also commonly known (or if you prefer - confused) and sold as the similar Prunus 'Mount Fuji', Prunus shirotae is a one of the most popular of all the ornamental flowering Japanese cherries. Like all selected forms this will be a grafted onto a rootstock either at the base of the tree or at the crown. Prunus serrula is often used for its ornamental bark or 'Colt', or Gisela 5. It is a vigorous tree with a wide spreading head of horizontal or drooping branches. The leaves a are bronze-green colour when young, turning to a mid-green as they mature, with a distinctive fringed appearance.

How to grow Prunus shirotae
It is noted for its profusion of fragrant, snow-white blooms which appear from late March to April. The flowers are single or semi-double, approximately 1-2cm across, and borne on long, drooping clusters.

Under favourable conditions (and depending on the rootstock) you can expect Prunus shirotae to reach a height of between 10-25 ft, with an approximate width of 15-35ft - depending on the rootstock.

It is best to plant Prunus shirotae in the autumn while the soil is still warm, but so long as you keep an eye on watering, container grown specimens can be planted any time of year. It is a shallow rooted selection that should not be planted too deeply nor should the soil around the base of the plant be cultivated too often or too deeply. It will be perfectly happy in most ordinary garden soils, preferably with a trace of lime. Just avoid soils that are prone to drying out over the summer or that become waterlogged during the winter.

Provide a position of full sun and stake with a stout support, especially in exposed areas. Pruning is not necessary other an to maintain a tidy shape or to remove weak, diseased or damaged branches.

Prunus shirotae was introduced to Western gardeners in 1905, and later received the Award of Garden Merit from the Royal Horticultural Society in 1984.


What is sea kale - Crambe maritima

If you have ever walked along the stoney coastlines of southern England, you may have chanced across the leathery, rosettes of our native sea kale - Crambe maritima. It is a mound-forming, spreading perennial related to the cabbage with large, fleshy, glaucous leaves. It produces dense racemes of small white flowers in early summer.

Sea kale can be found growing wild above the high tide mark on shingle beaches along the coasts of Europe, from the North Atlantic to the Black Sea.

It is an edible species, and has in fact been recorded as being served to none other than the Prince Regent George IV (1762–1830) at his seaside retreat - the Royal Pavilion in Brighton. The shoots are usually blanched for a better flavour and then steamed and served with a hollandaise sauce. Once cooked sea kale is said to have a flavour like a cross between asparagus and celery. Be aware that in the UK sea kale is protected under the Wildlife and Countryside Act (1981) and must not be picked without permission from the landowner.

Perhaps more interestingly, sea kale is a rare halophytic species, that is to say it is a plant which is capable either of of growing in waters of high salinity, or comes into contact with saline water through its roots or by salt spray. It is believed that only 2% of all plant species can be regarded as a halophyte.

Historical fact

Sea Kale is naturally high in vitamin C and was preserved and used by the Romans on long ocean journeys to prevent scurvy.

Click onto the above image for the 'Seeds of Eaden' seed shop
Main image - Siim CC BY-SA 2.5
In text image credit - Attribution: Andrew Hill cropped