marsh St. John's wort

These plants grow well in sun or in partial shade. Usually they tolerate more sun and heat if given enough moisture; in partial or light shade they need less moisture.

Herbaceous plants are not woody. Their stems are soft, usually remaining green. With some herabceous older stems may harden and look like woody stems (e. g. bamboo).

Leaves or needles remain on the plant for several consecutive years, usually 2 to 5 years. Our descriptions contain the word evergreen.

Plant can in otherwise appropriate environment survive cold down to - 23 °C.

Moist soil usually contain morefine clay parts and less sand, more humus and organic materials, they are somewhat heavier, but not hard; water does not run away quickly but stays among soil particles and is long available to plants. There is no stagnant water, soil is airy enough. Drought occurs rarely on such positions. Plants are given more or less permanent, moderate moisture.

Herbaceous, not woody plant. Stems and leaves may be evergreen or deciduous - thus regrowing every spring. Perennials may blossom consecutively for several years. Some perennials develop special underground organs - bulbs, corms or rootstocks and these species are treated separetelly, not with geophyte and tuberous plants.