Oenanthe javanica is a perennial herb that grows to about 1 m in height, with fibrous roots that emerge from all nodes, and flowers with 5 white petals and 5 stamens. The leaves are aromatic, glabrous, and have a sheath covering the stem. The leaflets are divided into lobes and crinkled.
In order to thrive, watercress must be kept permanently wet. It can grow submerged in water (as it does in a stream), but will do just as well in damp soil. The simplest way to achieve this is to sit your container in a deep saucer filled with water.
Potted watercress plants should use a soilless mix containing perlite or vermiculite combined with peat. Use a saucer beneath the plant and keep it filled with water to provide constant moisture.
The soil should retain moisture, bordering on wet but still draining. Celery prefers a soil with a pH between 5.8 and 6.8.
Celery production is best in a cool, humid and long growing season with an ample and uniform supply of moisture. Germination occurs at a minimum temperature of 5C with an optimum range of 15 to 21C, an optimum temperature of 21C and a maximum temperature of 30C.
Choose a container that is at least 8 inches deep and long enough to plant additional celery plants 10 inches apart. Don't use unglazed clay pots, if possible, as they dry out quickly and celery likes to stay moist. Plastic containers are a great choice in this instance, as they maintain moist conditions.
Hemlock Water Dropwort is always found growing close to water. The most poisonous plant in the UK and very common along most of our waterways.
