Artemisia absinthium is a probable parent of this hybrid, which has aromatic, silvery-grey foliage. Artemesia blends well with other perennials, acting as a foil or transition plant between possible clashing colors such as red and pink. These creamy white and appear from August to September. As with most perennials, the better prepared the soil, the better the performance of the plant. Because this perennial can get rather large, it is a perfect back-of-the-border plant, working well on slopes too. Divide spring or fall. Artemisia is found mainly in the Northern hemisphere and also parts of southern Africa and South America. Many species are used medicinally and for cooking.
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CharacteristicsCultivar: Powis Castle
Size: Height: 0 ft. to 2 ft.
Width: 0 ft. to 3 ft.
Plant Category: landscape, perennials, shrubs,
Plant Characteristics: low maintenance,
Foliage Characteristics: fragrant, evergreen,
Flower Color: yellows,
Tolerances: deer, drought, pollution, slope, wind,
Bloomtime Range: Late Summer to Late Summer
USDA Hardiness Zone: 7 to 9
AHS Heat Zone: 8 to 8
Light Range: Sun to Full Sun
pH Range: 4 to 8.5
Soil Range: Sand to Clay Loam
Water Range: Semi-Arid to Normal
FertilizingHow-to : Fertilization for Young Plants
Young plants need extra phosphorus to encourage good root development. Look for a fertilizer that has phosphorus, P, in it(the second number on the bag.) Apply recommended amount for plant per label directions in the soil at time of planting or at least during the first growing season.
How-to : Fertilization for Established Plants
Established plants can benefit from fertilization. Take a visual inventory of your landscape. Trees need to be fertilized every few years. Shrubs and other plants in the landscape can be fertilized yearly. A soil test can determine existing nutrient levels in the soil. If one or more nutrients is low, a specific instead of an all-purpose fertilizer may be required. Fertilizers that are high in N, nitrogen, will promote green leafy growth. Excess nitrogen in the soil can cause excessive vegetative growth on plants at the expense of flower bud development. It is best to avoid fertilizing late in the growing season. Applications made at that time can force lush, vegetative growth that will not have a chance to harden off before the onset of cold weather.
LightConditions : Types of Pruning
Types of pruning include: pinching, thinning, shearing and rejuvenating.
Pinching is removing the stem tips of a young plant to promote branching. Doing this avoids the need for more severe pruning later on.
Thinning involves removing whole branches back to the trunk. This may be done to open up the interior of a plant to let more light in and to increase air circulation that can cut down on plant disease. The best way to begin thinning is to begin by removing dead or diseased wood.
Shearing is leveling the surface of a shrub using hand or electric shears. This is done to maintain the desired shape of a hedge or topiary.
Rejuvenating is removal of old branches or the overall reduction of the size of a shrub to restore its original form and size. It is recommended that you do not remove more than one third of a plant at a time. Remember to remove branches from the inside of the plant as well as the outside. When rejuvenating plants with canes, such as nandina, cut back canes at various heights so that plant will have a more natural look.
Conditions : Full Sun
Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.
WateringConditions : 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 : Regular Moisture for Outdoor Plants
Water when normal rainfall does not provide the preferred 1 inch of moisture most plants prefer. Average water is needed during the growing season, but take care not to overwater. The first two years after a plant is installed, regular watering is important. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.
Conditions : Outdoor Watering
Plants are almost completely made up of water so it is important to supply them with adequate water to maintain good plant health. Not enough water and roots will wither and the plant will wilt and die. Too much water applied too frequently deprives roots of oxygen leading to plant diseases such as root and stem rots. The type of plant, plant age, light level, soil type and container size all will impact when a plant needs to be watered. Follow these tips to ensure successful watering:
* The key to watering is water deeply and less frequently. When watering, water well, i.e. provide enough water to thoroughly saturate the root ball. With in-ground plants, this means thoroughly soaking the soil until water has penetrated to a depth of 6 to 7 inches (1' being better). With container grown plants, apply enough water to allow water to flow through the drainage holes.
* Try to water plants early in the day or later in the afternoon to conserve water and cut down on plant stress. Do water early enough so that water has had a chance to dry from plant leaves prior to night fall. This is paramount if you have had fungus problems.
* Don't wait to water until plants wilt. Although some plants will recover from this, all plants will die if they wilt too much (when they reach the permanent wilting point).
* Consider water conservation methods such as drip irrigation, mulching, and xeriscaping. Drip systems which slowly drip moisture directly on the root system can be purchased at your local home and garden center. Mulches can significantly cool the root zone and conserve moisture.
* Consider adding water-saving gels to the root zone which will hold a reserve of water for the plant. These can make a world of difference especially under stressful conditions. Be certain to follow label directions for their use.
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.
PlantingHow-to : Preparing Garden Beds
Use a soil testing kit to determine the acidity or alkalinity of the soil before beginning any garden bed preparation. This will help you determine which plants are best suited for your site. Check soil drainage and correct drainage where standing water remains. Clear weeds and debris from planting areas and continue to remove weeds as soon as they come up.
A week to 10 days before planting, add 2 to 4 inches of aged manure or compost and work into the planting site to improve fertility and increase water retention and drainage. If soil composition is weak, a layer of topsoil should be considered as well. No matter if your soil is sand or clay, it can be improved by adding the same thing: organic matter. The more, the better; work deep into the soil. Prepare beds to an 18 inch deep for perennials. This will seem like a tremendous amount of work now, but will greatly pay off later. Besides, this is not something that is easily done later, once plants have been established.
How-to : 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.
ProblemsFungi : 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.
Fungi : Powdery Mildew
Powdery Mildew is usually found on plants that do not have enough air circulation or adequate light. Problems are worse where nights are cool and days are warm and humid. The powdery white or gray fungus is usually found on the upper surface of leaves or fruit. Leaves will often turn yellow or brown, curl up, and drop off. New foliage emerges crinkled and distorted. Fruit will be dwarfed and often drops early.
Prevention and Control: Plant resistant varieties and space plants properly so they receive adequate light and air circulation. Always water from below, keeping water off the foliage. This is paramount for roses. Go easy on the nitrogen fertilizer. Apply fungicides according to label directions before problem becomes severe and follow directions exactly, not missing any required treatments. Sanitation is a must - clean up and remove all leaves, flowers, or debris in the fall and destroy.
Fungi : Downy Mildew
Downy Mildew, a fluffy white fungal growth that develops on the underside of leaves, is most common during cool, humid conditions. Foliage often discolors and is stunted.
Prevention and Control: Use disease free plants and space far enough apart so that air circulation is good. Remove and discard infected leaves or even entire plants. Use a recommended fungicide and always follow the directions on the label.
MiscellaneousConditions : 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 : 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 : Low Maintenance
Low maintenance does not mean no maintenance. It does mean that once a plant is established, very little needs to be done in the way of water, fertilizing, pruning, or treatment in order for the plant to remain healthy and attractive. A well-designed garden, which takes your lifestyle into consideration, can greatly reduce maintenance.
Glossary : Rock Garden
A rock garden is a garden that mimics an alpine area, having dwarf conifers, low-growing sub-shrubs, perennials and ground cover. Often, the soil itself tends to be gravelly or rocky.
Glossary : Evergreen
Evergreen refers to plants that hold onto their leaves or needles for more than one growing season, shedding them over time. Some plants such as live oaks are evergreen, but commonly shed the majority of their older leaves around the end of January.
Glossary : Herbaceous
Herbaceous refers to a non-woody plant that dies back at the end of its growing season, generally after frost or during the fall of the year. The rootstock of perennials will overwinter, providing the plant is hardy in that area, and resume growth in the spring.
Glossary : Perennial
Perennial: traditionally a non-woody plant that lives for two or more growing seasons.
Glossary : Shrub
Shrub: is a deciduous or evergreen woody perennial that has multiple branches that form near its base.
Glossary : Fragrant
Fragrant: having fragrance.
Glossary : Long Lasting
Long Lasting: having blossoms that last for an extended period of time. Some plants may have the appearance of providing long lasting flowers because they are prolific, repeat bloomers.
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 : Small Shrub
A small shrub is less than 3 feet tall.
Glossary : Landscape Uses
By searching Landscape Uses, you will be able to pinpoint plants that are best suited for particular uses such as trellises, border plantings, or foundations.
Glossary : Tolerant
Tolerant refers to a plant's ability to tolerate exposure to an external condition(s). It does not mean that the plant thrives or prefers this situation, but is able to adapt and continue its life cycle.
Glossary : Drought Tolerant
Very few plants, except for those naturally found in desert situations, can tolerate arid soils, but there are plants that seem to be more drought tolerant than others. Plants that are drought tolerant still require moisture, so don't think that they can go for extended period without any water. Drought tolerant plants are often deep rooted, have waxy or thick leaves that conserve water, or leaf structures that close to minimize transpiration. All plants in droughty situations benefit from an occasional deep watering and a 2-3 inch thick layer of mulch. Drought tolerant plants are the backbone of xeriphytic landscaping.
Glossary : Fertilize
Fertilize just before new growth begins with a complete fertilizer.