Scutellaria

( skoot - ul - AIR - ee - uh )

At-A-Glance Information

This genus is often called Skullcap and includes species that require full sun to light shade and regular water to perform well in the landscape. Skullcap forms a clump of foliage and clusters of flowers and is easy to grow, as long as it has good drainage. These plants can be annual or perennial and reach between 2 and 40 inches tall when in bloom. Use Scutellaria in mixed beds or borders, to edge pathways, or as a no-traffic groundcover. they are commonly included in rock, woodland, shade, prairie, pollinator, and drought-tolerant gardens. Take care when planting these flowers in the garden, as some species can be toxic to humans and pets if ingested.

scutellaria Species and Varietals

Scutellaria is a genus in the plant family Lamiaceae and includes between 300 and 470 species. Plants in this genus are closely related to those in Lamium (Dead Nettle), Moluccella (Bells of Ireland) and Leonotis (Lion's Tail). The genus name is derived from the Latin word scutella, which means 'a small dish, tray, or platter', referring to the shape of the calyx. The best growing zones for Skullcap vary depending on the species cultivated. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Scutellaria alpina (Alpine Skullcap, Helmet Flower, Shlemnik Alpiysky, шлемник альпийский)
This species grows well in USDA hardiness zones 5-8 or Sunset growing zones 1-9 and 14-24, and is native to a region that spans from Southern Europe to Siberia. It typically forms a 6-inch tall, 1 foot wide dark green mat that produces tight clusters of purple or white (sometimes bicolored) flowers in late spring or early summertime. Plants prefer rocky soils and high elevations.

Scutellaria antirrhinoides (Snapdragon Skullcap, Nose Skullcap)
This wildflower species is native to the western United States, where it prefers to grow in forests, woodlands, and open rocky habitats. It is a perennial species which produces purple to bluish flowers with an area of white mottling on lower lips. This species thrives in USDA hardiness zones 5-8 or Sunset growing zones 4-9 and 14-17.

Scutellaria baicalensis (Baikai Skullcap, Chinese Skullcap, Huang-Qin, 黄芩, Shlemnik Baykal'skiy, шлемник байкальский, Golden Flower, Koganebana, 黄金花, Koganeyanagi, 黄金柳)
This species grows in USDA hardiness zones 4-9 or Sunset growing zones 1-9 and 14-24 and is native to Siberia, China and Japan. It forms a clump 1.5 feet tall and just as wide at maturity. Flowers are bluish purple and leaves are medium green. Blooms are present in summer and fall.

Scutellaria californica (California Skullcap)
Endemic to California, this species is found in scrub and low elevation mountains in the northern parts of the state. These plants are small, reaching just 20 inches tall when mature and in bloom. Flowers are small and white to yellow, and smell faintly of apples. Leaves are green and oppositely arranged. California Skullcap grows well in USDA hardiness zones 6b-10a or Sunset growing zones 1, 2, 6-10 and 14-17.

Scutellaria costaricana (Esutelaria, Scarlet Skullcap, Costa Rican Skullcap, Dragon's Tears, Tropical Skullcap)
These plants are commonly grown as tropical houseplants in many areas around the world. They are native to Panama and Costa Rica, and produce long, tubular scarlet flowers (occasionally rich yellow) with orange lips. They are suited for growing in USDA hardiness zones 9a-11.

Scutellaria lateriflora (Blue Skullcap, Mad Dog Skullcap, American Skullcap, Side-Flowering Skullcap)
These hardy perennials are native to North America, and have an upright habit with green foliage. Plants typically reach between 24 and 31 inches tall when in bloom, and love growing in wetlands, marshes, meadows and other moist landscapes. Flowers are blue and are are held along the length of side branches.

Scutellaria mexicana (Salazaria mexicana) (Bladder Sage, Paperbag Sage, Paperbag Bush)
These shrubs are known for their calyx lobes which develop into small bladder-like shells around fruits. They love gravelly or sandy substrates and grow in canyons and deserts in North America. Plants reach between 12 and 40 inches tall when in bloom, and flower between the months of April and June. Seed bags can last until wintertime in some areas.

Scutellaria nana (Dwarf Skullcap, Dwarf Scullcap, Little Skullcap)
These plants are native to the western United States, and often grow in scrub landscapes in volcanic soils. These small perennials reach 8 inches tall when in bloom, and form from rhizomatous roots. Flowers are typically multicolored, with tan, yellow, green, white and pink to purple tones. This species is suited for growing in USDA hardiness zones 4-7.

Scutellaria resinosa (Sticky Skullcap, Resinous Skullcap, Prairie Skullcap, Shrubby Skullcap, Escuteleria)
Native to a region that spans from Kansas and Colorado through northern Mexico, this species of Skullcap grows well in USDA hardiness zones 4-9 or Sunset growing zones 3-10 and 14-24. It reaches 6-8 inches tall and a foot wide, with grey-green foliage and deep purplish blue flowers that bloom in late springtime. Cultivars of this species bred for garden cultivation include 'Smoky Hills' (to 8-12 in. with grey-green leaves and purple blue flowers tipped with white) and 'Violet Cloud' (a hybrid with S. suffrutescens, with grey-green foliage and violet flowers).

Scutellaria suffrutescens (Escutelaria Mexicana, Escutelaria Rosa, Mexican Skullcap, Cherry Skullcap Texas Rose)
This plant, native to Mexico, grows well in zones 4-12 and 14-24. It reaches 6-8 inches tall and 12-18 inches wide, with pink flowers that bloom in summertime. This species is semi-evergreen and can take drought, heat and humidity.

Caring for scutellaria

Take care when planting these flowers in the garden, as some species can be toxic to humans and pets if ingested. Grow Scutellaria plants in full sun to partial shade. Ideally, they should be getting around 6 to 8 hours of sun each day with some shade in the afternoon when temperatures are at their peak (typically between 2 and 3 PM). Ensure that soil is well-draining, rich in nutrients, and has a pH of between 5.5 and 7.5 (acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, Skullcap species are generally drought tolerant, able to get by for much of the year on rainwater alone with supplemental irrigations during the drier months of the year. Some species, like Hoary Skullcap, appreciate more moisture.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. Every few years, these plants may need to be divided if flowering is declining. For instructions on how to successfully divide Skullcap plants, see the Propagation section below. Scutellaria plants can be expected to survive in the landscape for 3 to 5 years before needing to be replaced. They will naturally form offsets and clumps which can be divided, providing plants for the landscape indefinitely.

Caring for Scutellaria in Containers
Scutellaria flowers are commonly grown in containers, which brings their blooms into focus. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a well-draining potting mix amended with organic material and perlite, and top with a layer of mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Scutellaria plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

Scutellaria, or Skullcap, can be propagated by division, cutting or seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division or cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant, especially if you are propagating a hybrid cultivar. To propagate your Skullcap flowers, follow the instructions below:

Propagating Scutellaria by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed heads on plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will continue to split open and release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 2-6 weeks from sowing.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Propagating Scutellaria by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-4 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new plant.

Propagating Scutellaria by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout in the next growing season.