Collinsia

( kol - LIN - zee - uh )

At-A-Glance Information

Commonly called Chinese Houses or Blue Eyed Marys this California native plant blooms from spring to early summertime, and somewhat resemble Snapdragons. These annual flowers need partial shade in hotter climates, but can take full sun elsewhere and need regular waterings for best performance. The flowers will attract butterflies to your garden (especially Checkerspot Butterflies). Flowers held at the top of 1-2 foot tall stems are white and pink-purple, and these plants are great for adding color underneath trees, as bulb covers, or at the front of border gardens.

Collinsia species and varietals

the genus Collinsia includes 20 species and is a member of the family Plantaginaceae. The genus is named for Zacchaeus Collins, a Philadelphia botanist of the late 18th to early 19th century. They are best when grown in zones 1-24. To find your zone, click here: Zone Map. 

Collinsia barsiifolia (White Blue-Eyed Mary)
This species is endemic to California, where it grows in both mountain ranges and desert areas. These annuals produce slender stems and thick leaves. Flowers are borne in spaced whorls towards stem tips, and are white, lavender, or purple, and can be bicolored, as well. 

Collinsia callosa (Desert Mountain Blue-Eyed Mary)
This species, endemic to California, produces a somewhat fleshy, thick stem that is reddish green in color. Flowers are commonly bicolored white and bluish-pink. 

Collinsia childii (Child's Blue-Eyed Mary)
These plants are at home in woodland and chaparral natural landscapes in California's Sierra Nevadas and Coast Ranges. These annuals reach about 14 inches tall at maturity, and has stems covered in small hairs. Flowers are pale lavender in color and have two upper lobes and three lower lobes. 

Collinsia concolor (Chinese Houses)
Native to Southern California and Baja California, this species prefers to grow in woodland and chaparral landscapes. They reach about 18 inches tall in a single growing season, and produce purple-blue flowers with purple-dotted areas on the upper lobes. 

Collinsia corymbosa (Round-Headed Chinese Houses)
Endemic to the coastline of California north of the San Francisco Bay Area, this species is considered critically imperiled and produces a reddish-green stem that reaches about 10 inches tall. These plants can be erect or prostrate, and produce flowers that are white with a purple tint. 

Collinsia grandiflora (Giant Blue-Eyed Mary, Large-Flowered Collinsia)
These wildflowers are native to much of western North America, from British Colombia to northern California. These plants are at home in woodland and chaparral landscapes, and reach about 14 inches tall when mature. Stems are thin and leaves make the plant look like a native grass until they flower. Showy infloresences of pea-like flowers are white and purple-blue.

Collinsia greenei (Greene's Blue-Eyed Mary)
Endemic to northern California, this species produces a hairy stem up to a foot tall that holds royal purple flowers. Blooms sometimes have a white splash in their throats. 

Collinsia heterophylla (Collinsia bicolor) (Purple Chinese Houses, Innocence, Harlequin Blue Eyed Mary)
This flowering herbaceous annual plant is native to California and northern Baja California. This species likes a bit of shade, and naturally grows in the understory of woodland and forest areas. Blooms are present from spring through early summertime, and are purple with white upper lobes. The white lobes are dotted with purple-red markings.

Collinsia linearis (Narrowleaf Blue-Eyed Mary)
These plants are native to the conifer forests in northern California and Oregon, and have narrower leaves than other species. The flowers produced by these plants are white to lavender-tinted, and is sometimes seen with darker blooms that can be bicolored, as well. 

Collinsia multicolor (San Francisco Blue-Eyed Mary, San Francisco Collinsia)
These plants have a native range between San Francisco and Santa Cruz, California, and prefer to grow in moist, shaded habitats in forested areas. These plants are threatened with extinction due to human activity. Stems and upper parts of plants are somewhat sticky. Upper lobes of flowers are white, sometimes marked with purple, and lower lobes are purple to lavender.

Collinsia parryi (Parry's Blue-Eyed Mary)
This spindly species is endemic to central and southern California, and produces lavender to purple clowers that are flushed with white towards the upper lobes, which are sometimes also dotted with reddish-purple.

Collinsia parviflora (Maiden Blue-Eyed Mary, Small-Flowered Collinsia)
These tiny wildflowers are found throughout western North America, and prefer to grow in moist, shaded environments within mountain forests. These annuals produce a spindly, reddish stem and miniscule blue to purple and white flowers. 

Collinsia rattanii (Sticky Blue-Eyed Mary)
These plants are native to the Pacific Northwest, from Washington down through northern California. These annuals reach 16 inches tall at maturity, and produce white and purple flowers. Leaf undersides are purple, uppers are green.

Collinsia sparsiflora (Spinster's Blue-Eyed Mary, Few-Flowered Collinsia)
These plants are native to the west coast of the United States, from Washington down through northern California. This species produces plants which reach about a foot tall when mature, and have reddish stems. Flowers are commonly purple, white, or lavender. 

Collinsia tinctoria (Sticky Chinese Houses, Tincture Plant)
​These plants are endemic to northern and central California's mountainous areas. They can reach up to 2 feet tall when mature, and produce flowers that are white to yellow to purple, often with darker lining and markings towards the throats. The sap from these plants will leave stains on anything they touch.

Collinsia torreyi (Torrey's Blue-Eyed Mary)
Native to California, Oregon, and Nevada, this species produces a reddish stem up to 10 inches tall when mature. Plant parts are somewhat sticky and hairy, especially towards the top of the flower inflorescence. Blooms are small, usually bicolored purple and white. 

Collinsia verna (Blue-Eyed Mary)
These eastern and central United States native plants grow in moist valley bottoms and sloped areas, and prefers shady spots. Flowers are blue-purple and white.

Caring for collinsia

Plant Chinese Houses in early springtime. Plants can be purchased as starts from a reputable nursery or grown from seed (direct sown or pre-seeded). They are commonly planted in the ground, as well as in beds and containers. In windy areas, taller species and varieties will need to be staked to prevent damage or flopping over. Collinsia should be planted in a spot in the garden that receives full sun during the day. Ideally, these flowers prefer to get between 6 and 8 hours of sun each day. Not enough sunlight will result in a leggy plant that produces fewer flowers, though they do appreciate some late afternoon shade, especially in the warmer regions of their zone range. Collinsias like a rich, well-draining soil medium. 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. After planting, apply a thick layer of mulch around the planting area to suppress weed growth, increase soil moisture retention, and maintain a constant soil temperature. Ensure that mulch does not go right up to the stems, as this creates an environment that favors fungal diseases.

Water new plantings regularly as they develop a strong root system. At maturity Collinsias prefer frequent waterings to bloom well. This is especially true in high heat situations. As a general rule of thumb, water whenever the top inch of soil feels dry. Two to three times during the growing season from spring through fall, pinch plants back by about an inch to encourage a strong branching system to develop. Fertilize yearly in early springtime with a 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. Deadhead flowers to improve the appearance of plants over their blooming season and to discourage reseeding.

Propagation

Collinsia, or Chinese Houses, can be propagated either by cutting, division or from 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. To propagate your Chinese Houses, follow the instructions below:

Propagating Collinsia by Cutting
  1. 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. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand.
  2. In spring or 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 6 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.
  3. 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.
  4. 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 Collinsia by Seed
  1. 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. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. 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.
  3. In either late winter or early springtime, 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. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  4. 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.
Collinsia seed pods are left behind after flowers have faded.
Collinsia seeds are very small, and are typically dark brown to reddish-brown in color.

Problems and Pests

Collinsia plants, although typically quite resilient, can be susceptible to developing problems with the following pests and diseases in the garden:
  • Aphids
  • Spider Mites
  • Powdery Mildew
  • Root Rot
For more information on these problems, including how to treat and prevent them, consult the following pages:

Gallery

Collinsia flowers look fantastic when planted in masses.
Bumblebees and other pollinators are drawn to these flowers in the landscape.
Here, Collinsia is grown at the base of a garden bench for a pop of color.
This California landscape features Poppies and Collinsia.
Flowers are borne in whorls towards the tip of stems that rise above the foliage.
This native garden features Poppies and Collinsia.

Videos

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Resources

How to Propagate Collinsia heterophylla
Collinsia Plant Growing and Care Guide for Gardeners
Purple Chinese Houses
Collinsia heterophylla (Purple Chinese Houses)
Wikipedia: Collinsia
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 257, Collinsia heterophylla (Chinese Houses)
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