St John’s Wort Plant Care

For a basket of sunlight in the garden, add the St John’s wort to your landscape. One thing is for sure the yellow flowers will share a remarkable light for all to see in the garden.

Furthermore, the shrub will provide you with abundant blooms throughout the year.

Another exciting thing is people usually refer to it as God’s wonder plant for its medicinal uses.

Plant Name: Hypericum perforatum

Other Name: Common St. John’s wort, Klamath weed, goatweed, Tipton weed, devil’s scourge, rosinweed, God’s wonder plant, perforate St. John’s wort

Plant Type: Herbaceous perennial

Native Areas: Europe, Southwestern Asia, and North Africa; has naturalized in North America

Light Requirement: Full sun to partial shade

Watering: Average

Fertilizer: Compost

Toxicity: Large amounts are toxic to humans and pets

Temperature: Warm Temperatures

Propagation: Seed

Growth: 1 to 3 feet tall and 1 feet wide

Soil Type: Well-drained soil

USDA Hardiness Zones: 4-8

More About St John’s Wort Plant

Hypericum perforatum or the more common name is St. John’s wort, but there are many others in the folklore. Furthermore, you can find over 400 cultivars alone in the genus and family. The plant St John’s wort comes from Europe, North Africa, and Asia.

Yet, it has neutralized in North America, and the Hypericum perforatum is the true St John’s wort plant. It is a small herbaceous shrub that blooms yellow flowers on red-brown upright ribbed stems.

The Hypericum plants have blue-green foliage covered with translucent dots that grow in opposite pairs. The new growth sprouts out in yellow-green clusters and has started shaping yellow flowers.

The plant belongs to the Hypericum genus, and once the flower buds fade, you see red berries or seed heads forming with tiny brown to black seeds. While it is a small shrub, it has an extensive root ball system, and removing it from the garden is difficult.

These outdoor plants also self-seed, which can cause huge maintenance issues, and they are invasive species in some countries classified as noxious weeds.

St John’s Wort Care Guide

St John’s wort is a low-maintenance plant that adapts well in the garden. When it becomes established, it needs little care but a watchful eye to prevent them from spreading.

Planting St John’s Worts

You can grow St John’s wort from seedlings, seeds, and cuttings. But first, sow seeds indoors about eight weeks before the last frost date.

You can plant a mature St John’s at any time of the year after the last frost. Still, we recommend growing them from spring to fall.

You can also grow St John’s wort in containers or as a shrub border if permitted in the area. Some species you can grow as ground cover as well.

Recommended Soil For St John’s Wort

St John’s wort grows in different soil types. Hence, it can grow in clay, loam, or sandy soil that is acidic or alkaline to even poor soils to compacted ground. But it does prefer well-drained soil with an average moisture content.

Provide your St John’s wort with added compost and building sand for compacted soil.

Lighting Needs and Temperature

The sun to temperature depends on where you live. In southern parts with hot climates grow St John’s wort in partial shade.

While in the northern climates, where it is cooler, you can grow them in full sun.

The plant can tolerate both full sun to full shade. Still, the plant suffers if the temperatures remain above 75ºF (24 ºC). The same goes for too much shade, which can stunt the growth.

You can grow St John’s wort in the USDA growing zones 5 to 10 outdoors, but your plant’s roots will need protection with a winter mulch in cold temperatures.

Watering and Humidity For St John’s Wort

The St John’s wort tolerates moist soil, especially young plants until the root system becomes established. Still, it is drought-tolerant for a short while and can survive flooding. The best is to water directly at the soil line, and during long periods of drought, you will need to water more and do not need watering in winter.

Still, it does not enjoy waterlogged soil.

Fertilizing in Early Spring

All your herb John wort needs is an organic mulch in early spring to keep them growing in the growing season. You can fertilize your plants if grown in poor soil to help them show off those beautiful St John’s wort blooms in summer to early fall.

Pruning St John’s Wort

You need not prune the plant growth unless you need to do re-shaping or it looks untidy. The Klamath weed flowers develop on old wood; thus, pruning St John’s wort new foliage in early spring will help stimulate the growth to flower again.

You can remove the spent flowers when the blooming season ends.

Potting

If you prefer to control the invasive growth of the plant, you can provide them with potting soil in containers with enough drainage holes. Hence during winter temperatures, you can bring your potted plant indoors out of the cold. Also, remember to keep the soil moist but not soggy.

In many parts, the plant grows as a deciduous shrub and makes for excellent ornamental cultivars indoors and outside.

Propagating The Noxious Weed

You can propagate and grow St John’s wort in three ways.

First Method:

• Start seeds in module cells indoors in spring to plant outside after the last frost date.

• Or sow seeds directly outside after the frost passes. Prepare a spot with a lot of compost and press the seed gently into the soil and water well.

• Germination can take up to 20 days, and you will need to thin out seedlings to one foot, or you can sow seeds in the fall for transplanting in late spring.

Second Method:

• Cut softwood cutting from the new non-flowering growth in early spring about four inches long with a leaf bud.

• Remove the lower leaves, dip the cut end into a rooting hormone, and stick it into potting soil mixed with perlite and compost.

• Once the roots form, you can transplant the cutting into the garden.

Third Method:

• The last method is through division done in spring or early fall.

• Dig up the root ball and tease the roots apart.

• Cut the roots in half to get two sections.

• Replant the divisions into a location in the garden or into pots and water well until they become established.

St John’s Wort Plant Varieties

There are a few St John’s wort varieties that are very interesting:

• Hypericum andosaemum is a low-growing evergreen hedge that does not grow taller than 32 inches. It bears small yellow flowers.

• Hypericum citrinum has bright lemon-like flowers making for a beautiful ornamental display.

• Hypericum inodorum is a hardy plant and can bloom numerous flowers.

• Hypericum moserianum has mottle pink with green leaves making it very appealing in the garden. The buds are pink and have a yellow hue once it bursts open.

St John’s Wort Plant Common Diseases and Pests

When it comes to pests, the St John’s wort is not bothered by them, and it is disease-free most of the time. The only problem is root rot that happens from overwatering.