Rheum palmatum ( Chinese Rhubarb )

Characteristics

Cultivar:	n/a
Family:	Polygonaceae
Size:	Height: 0 ft. to 8 ft. Width: 0 ft. to 6 ft.
Plant Category:	perennials,
Plant Characteristics:	poisonous,
Foliage Characteristics:
Foliage Color:	dark green,
Flower Characteristics:	long lasting, unusual,
Flower Color:	greens, reds,
Tolerances:

Requirements

Bloomtime Range:	Early Summer to Late Summer
USDA Hardiness Zone:	5 to 9
AHS Heat Zone:	Not defined for this plant
Light Range:	Part Shade to Sun
pH Range:	4.5 to 6.5
Soil Range:	Sandy Loam to Clay Loam
Water Range:	Normal to Moist

Plant Care

Fertilizing

How-tos : Fertilization for Annuals and Perennials

Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.

Light

Conditions : Full to Partial Sun

Full sunlight is needed for many plants to assume their full potential. Many of these plants will do fine with a little less sunlight, although they may not flower as heavily or their foliage as vibrant. Areas on the southern and western sides of buildings usually are the sunniest. The only exception is when houses or buildings are so close together, shadows are cast from neighboring properties. Full sun usually means 6 or more hours of direct unobstructed sunlight on a sunny day. Partial sun receives less than 6 hours of sun, but more than 3 hours. Plants able to take full sun in some climates may only be able to tolerate part sun in other climates. Know the culture of the plant before you buy and plant it!

Watering

Conditions : Moist

Moist is defined as soil that receives regular watering to a depth of 18 inch deep, does not dry out, but does not have a drainage problem either.

Conditions : Normal Watering for Outdoor Plants

Normal watering means that soil should be kept evenly moist and watered regularly, as conditions require. Most plants like 1 inch of water a week during the growing season, but take care not to over water. The first two years after a plant is installed, regular watering is important for establishment. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.

Planting

How-tos : Planting Perennials

Determine appropriate perennials for your garden by considering sun and shade through the day, exposure, water requirements, climate, soil makeup, seasonal color desired, and position of other garden plants and trees.

The best times to plant are spring and fall, when soil is workable and out of danger of frost. Fall plantings have the advantage that roots can develop and not have to compete with developing top growth as in the spring. Spring is more desirable for perennials that dislike wet conditions or for colder areas, allowing full establishment before first winter. Planting in summer or winter is not advisable for most plants, unless planting a more established sized plant.

To plant container-grown plants: Prepare planting holes with appropriate depth and space between. Water the plant thoroughly and let the excess water drain before carefully removing from the container. Carefully loosen the root ball and place the plant in the hole, working soil around the roots as you fill. If the plant is extremely root bound, separate roots with fingers. A few slits made with a pocket knife are okay, but should be kept to a minimum. Continue filling in soil and water thoroughly, protecting from direct sun until stable.

To plant bare-root plants: Plant as soon as possible after purchase. Prepare suitable planting holes, spread roots and work soil among roots as you fill in. Water well and protect from direct sun until stable.

To plant seedlings: A number of perennials produce self-sown seedlings that can be transplanted. You may also start your own seedling bed for transplanting. Prepare suitable planting holes, spacing appropriately for plant development. Gently lift the seedling and as much surrounding soil as possible with your garden trowel, and replant it immediately, firming soil with fingertips and water well. Shade from direct sun and water regularly until stable.

Problems

Fungi : Rusts

Most rusts are host specific and overwinter on leaves, stems and spent flower debris. Rust often appears as small, bright orange, yellow, or brown pustules on the underside of leaves. If touched, it will leave a colored spot of spores on the finger. Caused by fungi and spread by splashing water or rain, rust is worse when weather is moist.

Prevention and Control: Plant resistant varieties and provide maximum air circulation. Clean up all debris, especially around plants that have had a problem. Do not water from overhead and water only during the day so that plants will have enough time to dry before night. Apply a fungicide labeled for rust on your plant.

Diseases : Southern Blight

Plants with Southern blight have lesions on the stem at, or near, the soil line. These lesions develop rapidly, girdling the stem and resulting in a sudden and permanent wilting of the plant. High temperatures (above 85 degrees F, 29 degrees C) favor the disease. The fungus attacks a wide range of plants and survives for long periods in soil. To control, treat with a recommended fungicide according to label directions.

Miscellaneous

Glossary : Rhizome

A thickened modified stem that grows horizontally along or under the soil surface. It may be long and slender, as in some lawn grasses, or thick and fleshy, as with rhubarb.

Glossary : Poisonous

Poisonous: any plant or part of a plant which is toxic or irritating in any way.

Glossary : Perennial

Perennial: traditionally a non-woody plant that lives for two or more growing seasons.

Glossary : pH

pH, means the potential of Hydrogen, is the measure of alkalinity or acidity. In horticulture, pH refers to the pH of soil. The scale measures from 0, most acid, to 14, most alkaline. Seven is neutral. Most plants prefer a range between 5.5 and about 6.7, an acid range, but there are plenty of other plants that like soil more alkaline, or above 7. A pH of 7 is where the plant can most easily absorb the most nutrients in the soil. Some plants prefer more or less of certain nutrients, and therefore do better at a certain pH.

Glossary : U. S. Natives

Native plants require lower maintenance and usually have less pest problems. They are key components in the xeriphytic landscape and backyard wildlife habitat. Select your region and the search will look for all plants in the database that are native to your area.

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