Toxic Taxus baccata

Taxus baccata has deep dark green needles all year round. It is an evergreen tree that is also often used as a hedge. In winter, Taxus bears red fruits that are much loved by birds, but very poisonous to ungulates.

Taxus baccata is usually a sturdy shrub that, if given space, can grow into a tree. Growth is slow but eventually the tree can reach a height of about 15 to 20 meters with a width of 12 to 15 meters. The species is widely used for hedges and also for topiary. Bulbs, cones, columns and even animal shapes are available. Taxus can tolerate very strong pruning, even down to the perennial wood.

Myriophyllum beautiful but a nuisance

Myriophyllum or Red stem is a water plant that prefers to take root on the transition from land to water. The stems can grow up to 2 meters long and protrude a few decimetres above the water. Red stem grows particularly well in shallow, warm and nutrient-rich waters. The plant usually roots in shallow riparian zones, but free-floating stems without roots can also survive in nutrient-rich deep water. Red stem is originally from South America.

Myriophyllum was imported for trade in pond and aquarium plants. The plants come into nature because people throw away excess plants in public waters, after which they can spread further.

Sambucus, breathing through the cork layer

Cork is formed by a cambium layer that itself almost always arises as secondary meristem from the collenchyma or parenchyma layer directly under the epidermis. Unlike sclerenchymal cells, collenchymal cells are still alive and have retained the ability to differentiate. Cork cambium cells only divide periclinally, creating the typical rows of daughter cells. In this way mainly cork cells are produced to the outside and to a much lesser extent (sometimes not at all) cork parenchyma is produced to the inside. Cork cambium, cork cells and cork parenchyma together are also called periderm. Developed cork cells are dead and their cell walls contain suberine, a greasy substance that repels water.

It looks like a miniature pine forest

Hippuris vulgaris or Marestail is a common swamp and pond plant. This plant is counted among the oxygen plants because the underwater leaves also produce a lot of oxygen and it resembles Elodea (waterweeds) The piece that is a few decimeters above the water looks like a small pine tree. Marestail can form large masses and propagate by means of rhizomes. It prefers to grow on clay soil and in particular in brackish water. A Marestail field looks like a miniature pine forest.

The open structure of a water plant

Hippurus (Hippuris) vulgaris or mare’s-tail is a very common swamp and pond plant. This plant (a helophyte) is counted among the oxygen plants because the underwater leaves also produce a lot of oxygen and resemble water plague (Elodea). But the piece that raises a few decimeters above water looks like a small pine tree. Mare’s-tail can form large masses and continue spreading through means of rhizomes. Mare’s-tail grows preferably on clay soil and especially in brackish water.

From North America to anywhere else

Ceratophyllum demersum is a native of North America. It now has a worldwide distribution, at least in part due to the aquarium and pond trade. It is a submerged aquatic plant which is capable of forming dense monospecific beds, excluding other plant species, causing problems to recreational activities on waterways and in some cases causing blockages at hydroelectric power stations. C. demersum can spread rapidly, and grows in a large range of aquatic habitats.

Gooseberries under attack

Powdery mildew (Sphaerotheca mors-uvae) severely infects young shoots, stems and fruits of gooseberry (Ribes uva-crispa). Environmental friendly and biological control measures are being sought throughout the world. Especially in organic currant growing, effective control measures are needed, because powdery mildew infections may result in a total loss of the crop. In organic currant growing the number of adequate control methods is very limited.