Onopordum acanthium ( Scotch Thistle )

Characteristics

Cultivar:	n/a
Family:	Asteraceae
Size:	Height: 0 ft. to 6 ft. Width: 0 ft. to 3 ft.
Plant Category:	annuals and biennials,
Plant Characteristics:	seed start, spreading,
Foliage Characteristics:	coarse leaves,
Foliage Color:	green, silver to cream,
Flower Characteristics:	long lasting,
Flower Color:	pinks, purples,
Tolerances:	deer, drought, heat & humidity, pollution, rabbits, seashore, slope, wind,

Requirements

Bloomtime Range:	Mid Summer to Late Summer
USDA Hardiness Zone:	6 to 9
AHS Heat Zone:	7 to 12
Light Range:	Full Sun to Full Sun
pH Range:	5.5 to 8.5
Soil Range:	Mostly Sand to Some Clay
Water Range:	Semi-Arid to Dry

Plant Care

Fertilizing

Light

Conditions : Full Sun

Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.

Watering

Conditions : Dry

Dry is defined as an area that regularly receives water, but is fast draining. This results in a soil that is often dry to a depth of 18 inches.

Conditions : Normal

Normal is defined as regular watering to a depth of 18 inches, but periodically dries out in the top 7 inches between waterings.

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

Problems

Pest : Slugs and Snails

Slugs and snails favor moist climates and are mollusks, not insects. They can be voracious feeders, eating just about anything that is not woody or highly scented. They may eat holes in leaves, strip entire stems, or completely devour seedlings and tender transplants, leaving behind tell-tale silvery, slimy trails.

Prevention and control: Keep your garden as clean as possible, eliminating hiding places such as leaf debris, over-turned pots, and tarps. Groundcover in shady places and heavy mulches provide protection from the elements and can be favorite hiding places. In the spring, patrol for and destroy eggs (clusters of small translucent spheres) and adults during dusk and dawn. Set out beer traps from late spring through fall.

Many chemical controls are available on the market, but can be poisonous and deadly for children and pets; take care when using them - always read the label first!

Pest : Caterpillars

Caterpillars are the immature form of moths and butterflies. They are voracious feeders attacking a wide variety of plants. They can be highly destructive and are characterized as leaf feeders, stem borers, leaf rollers, cutworms and tent-formers.

Prevention and Control: keep weeds down, scout individual plants and remove caterpillars, apply labeled insecticides such as soaps and oils, take advantage of natural enemies such as parasitic wasps in the garden and use Bacillus thuringiensis (biological warfare) for some caterpillar species.

Miscellaneous

Conditions : Deer Tolerant

There are no plants that are 100% deer resistant, but many that are deer tolerant. There are plants that deer prefer over others. You will find that what deer will or will not eat varies in different parts of the country. A lot of it has to do with how hungry they are. Most deer will sample everything at least once, decide if they like it or not and return if favorable. A fence is the good deer barrier. You may go for a really tall one (7 to 8 feet), or try 2 parallel fences, (4 to 5 feet apart). Use a wire mesh fence rather than board, since deer are capable of wiggling through a 12 inch space.

Conditions : Pollution Tolerant

Air pollution is becoming a bigger problem each day. Pollutants in our air damage plants. The plants are damaged by absorbing sulfur dioxide, ozone, peroxyacetyl nitrate, ethylene, and nitrogen dioxide through their pores. Cell membrane damage may result in leaf drop, blotched or burnt looking leaves, or off-colored tissue between veins. Vehicles and industrial processes are the key culprits and conditions worsen on hot summer days. Though planting only pollution tolerant plants is not the solution to this problem, it is a visual band aid. Your Cooperative Extension Service may have a list of plants that are more pollution tolerant in your area.

Conditions : Rabbit Tolerant

As cute as they are, rabbits can really damage a vegetable garden. Young, tender lettuce plants seem to be their favorite. If a free-roaming dog is not a possibility for you, consider installing raised vegetable beds and covering tender shoots with netting. If you have ample room, you can opt to plant enough for you and the bunnies. Scents don't always repel animals, as they get used to them and are often washed off in the rain.

Conditions : Slope Tolerant

Slope tolerant plants are those that have a fibrous root system and are often plants that prefer good soil drainage. These plants assist in erosion control by stabilizing/holding the soil on slopes intact.

Conditions : Wind Tolerant

Plants that are wind tolerant usually have flexible, strong branches that are not brittle. Wind tolerant plants often have thick or waxy leaves that control moisture loss from whipping winds. Native plants are often the best adapted to not only wind, but also soil and other climatic conditions.

Glossary : Biennial

Biennial is a plant that takes two growing seasons to produce flowers and fruit. The first growing season, the plant stays in a rosette form, producing mainly foliage and roots. The second growing season the plant bolts, producing flowers and fruits or seeds.

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.

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