Land Cress or Barbarea Verna is a wonderful plant for the home vegetable garden as a dead end trap for the eggs of butterflies, like the cabbage butterfly. The caterpillars hatch and die after eating the leaves of the land cress which is rich in saponins and toxic to the caterpillars. In doing so it acts as a biological pest control agent.
This beneficial plant is easy to grow and has delicious, peppery leaves to add to a mixed salad. Land cress is also rich in vitamins, iron and calcium.
Growth habits and planting needs
Land cress is biennial and a hardy plant that will grow in full sun or even in part shade. It is slow growing.
Given its attractiveness to cabbage butterflies and its protective value in the garden it is an excellent plant to use as a border around a garden bed. Do plant it near your leafy vegetables and brassicas.
Land cress prefers a soil that drains well and is fertile for optimal growth, though it can grow in many soil types successfully. So prepare the selected site well by digging it over to a depth of about 20 cm, removing clods and stones.
Land cress does best in soil with a pH of 6.0 to 6.8 so test your soil and amend it if necessary. Add garden lime or dolomite if the soil pH is low, or too acidic, or dig in well rotted compost and aged manure if the soil pH is high or too alkaline. Do this at least a four weeks before sowing so that the nutrients will be available to the developing seedlings.
As a leafy plant that is nitrogen dependant for strong growth of leaves and stems, the land cress should follow nitrogen fixing legumes in the crop rotation system.
In temperate climates like Sydney, land cress can be sown from January to December. In our garden we are just harvesting the seeds from our plants that have been growing well for 2 years and have just gone to seed. We have also left some plants in place to self sow.
Water the soil before planting. Sow the seeds 0.5 cm deep and keep the soil moist until germination. The seedlings will emerge in 8-15 days.
When the land cress seedlings have two true leaves thin the plants by choosing the strongest ones and clipping the others out with small scissors, spacing to about 7 cm apart and thin again later when the plants are bigger.Add your clippings to your mixed leaf salad.
The full grown plant has a spread of about 30 cm across so will need enough space between plants. We have successfully moved seedlings to new positions so do this if the plants are growing too closely.
Keep the land cress well watered throughout its growth and mulch around the plants to prevent weeds and to conserve moisture by preventing evaporation.
Watering is best achieved with drip irrigation which keeps the leaves dry. If you do not have this type of watering system, give the plants good soaks by watering at the base of the plant early in the day to allow any splash on the leaves to dry. This will avoid mildew developing.
Land cress will mature in 8 weeks and can then be used as a ‘cut and come again’ salad leaf.Pick the young leaves around the bottom of the plant taking care to leave the stem and roots in place so the plant can grow further. Harvesting the leaves will encourage further growth. Even if you are growing the plant to protect your brassicas harvesting some of the leaves will benefit the plant and keep it growing vigorously and replacing itself with new leaves.
All parts of the land cress plant are edible and you can use the leaves in any recipe that you would use regular cress, such as in sandwiches, salads and soups. Even the flowers are edible and will make a delightful garnish to your salads.
Wash the leaves and dry them and store them between kitchen paper in breathable vegetable bags and store in the fridge for 4-5 days.
After 2 years the plant will start to go to seed and produces its flowers and then seeds. Save your strongest, healthiest plants to keep for seed saving.
After a month the plant will be in flower.
You can then stake the plants to keep the stems upright until the seed have fully dried out.
Two months from the flowers starting to form the seeds have yellowed and plumped out. In Sydney this is in mid to late December.
When harvesting the seeds, place a large bag over the plant and cut the stem at the ground. Turn the bag up with the pans upside down and allow the seeds to dry for a futher period of time till the seed pods are brittle and dry.
Shake the seeds out into the bag and rub the seed pods to release the small seeds. Collect them and place them into paper envelopes and label them with the date collected and the location origin of the plant.
You can get some further information on aspects of seed saving at the article at this link.
Also at this link you will find the details for downloading the seed packet template below to make your own seed packets created by Rosemary Beck so check it out by clicking at the link above.