This annual is grown for its attractive silver-gray foliage and mounding form. ‘Silver Queen’ is a compact variety with silvery-white, lacy leaves, and grows to 8″ tall and wide. Can over winter and act like a perennial in warmer areas, or if mulched heavily. Flowers are mustard-yellow, held in corymbs, and are produced in the second year. Shear or pinch back plants if they become leggy. Tolerant of many soils, prefers full sun and well drained site. An excellent foil between brightly colored bedding plants. Often used as an edging or border plant.
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CharacteristicsCultivar: Silver Queen
Size:Height: 0.67 ft. to 0.67 ft.
Width: 0.67 ft. to 0.67 ft.
Plant Category:annuals and biennials, perennials, shrubs,
Foliage Characteristics:medium leaves,
Tolerances:deer, drought, heat & humidity, pollution, rabbits, seashore, slope, wind,
Bloomtime Range: Mid Summer to Early Fall
USDA Hardiness Zone:8 to 10
AHS Heat Zone:Not defined for this plant
Light Range:Sun to Full Sun
pH Range:Not defined for this plant
Soil Range:Some Sand to Clay Loam
FertilizingHow-to : 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.
LightConditions : Full Sun
Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.
WateringConditions : 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 and Removing Annuals
When planting annuals, begin by preparing the soil. Rototill rotted compost, soil conditioner, pulverized bark, or even builders sand into the existing soil and rake it smooth. Annuals grow quickly, so space them as recommended on plant tags. Remove plants from their containers or packs gently, being sure to keep as much soil as you can around the root ball. If the rootball is tight, loosen it a bit by gently separating white, matted roots with your fingers or a pocket knife. Plant at the same depth they were in the containers. Gently fill in around the plants, providing support but not cutting off air to the roots. Water the plants well.
Through the season, be sure to fertilize for optimal performance. Take special care to cut back or completely remove any diseased plants, as soon as you see there is a problem. At the end of the season, be sure to remove all plants and their root balls. Rake the bed well to prepare it for the next season's planting.
How-to : Pruning Flowering Shrubs
It is necessary to prune your deciduous flowering shrub for two reasons: 1. By removing old, damaged or dead wood, you increase air flow, yielding in less disease. 2. You rejuvenate new growth which increases flower production.
Pruning deciduous shrubs can be divided into 4 groups: Those that require minimal pruning (take out only dead, diseased, damaged, or crossed branches, can be done in early spring.); spring pruning (encourages vigorous, new growth which produces summer flowers - in other words, flowers appear on new wood); summer pruning after flower (after flowering, cut back shoots, and take out some of the old growth, down to the ground); suckering habit pruning (flowers appear on wood from previous year. Cut back flowered stems by 1/2, to strong growing new shoots and remove 1/2 of the flowered stems a couple of inches from the ground) Always remove dead, damaged or diseased wood first, no matter what type of pruning you are doing.
Examples: Minimal: Amelanchier, Aronia, Chimonanthus, Clethra, Cornus alternifolia, Daphne, Fothergilla, Hamamelis, Poncirus, Viburnum. Spring: Abelia, Buddleia, Datura, Fuchsia, Hibiscus, Hypericum, Perovskia, Spirea douglasii/japonica, Tamarix. Summer after flower: Buddleia alternifolia, Calycanthus, Chaenomeles, Corylus, Cotoneaster, Deutzia, Forsythia, Magnolia x soulangeana/stellata, Philadelphus, Rhododendron sp., Ribes, Spirea x arguta/prunifolia/thunbergii, Syringa, Weigela. Suckering: Kerria
How-to : Preparing Containers
Containers are excellent when used as an ornamental feature, a planting option when there is little or no soil to plant in, or for plants that require a soil type not found in the garden or when soil drainage in the garden is inferior. If growing more than one plant in a container, make sure that all have similar cultural requirements. Choose a container that is deep and large enough to allow root development and growth as well as proportional balance between the fully developed plant and the container. Plant large containers in the place you intend them to stay. All containers should have drainage holes. A mesh screen, broken clay pot pieces(crock) or a paper coffee filter placed over the hole will keep soil from washing out. The potting soil you select should be an appropriate mix for the plants you have chosen. Quality soils (or soil-less medias) absorb moisture readily and evenly when wet. If water runs off soil upon initial wetting, this is an indicator that your soil may not be as good as you think.
Prior to filling a container with soil, wet potting soil in the bag or place in a tub or wheelbarrow so that it is evenly moist. Fill container about halfway full or to a level that will allow plants, when planted, to be just below the rim of the pot. Rootballs should be level with soil line when project is complete. Water well.
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.
ProblemsPest : Spider Mites
Spider mites are small, 8 legged, spider-like creatures which thrive in hot, dry conditions (like heated houses). Spider mites feed with piercing mouth parts, which cause plants to appear yellow and stippled. Leaf drop and plant death can occur with heavy infestations. Spider mites can multiply quickly, as a female can lay up to 200 eggs in a life span of 30 days. They also produce a web which can cover infested leaves and flowers.
Prevention and Control: Keep weeds down and remove infested plants. Dry air seems to worsen the problem, so make sure plants are regularly watered, especially those preferring high humidity such as tropicals, citrus, or tomatoes. Always check new plants prior to bringing them home from the garden center or nursery. Take advantage of natural enemies such as ladybug larvae. If a miticide is recommended by your local garden center professional or county Cooperative Extension office, read and follow all label directions. Concentrate your efforts on the undersides of the leaves as that is where spider mites generally live.
Pest : Whiteflies
Whiteflies are small, winged insects that look like tiny moths, which attack many types of plants. The flying adult stage prefers the underside of leaves to feed and breed. Whiteflies can multiply quickly as a female can lay up to 500 eggs in a life span of 2 months. If a plant is infested with whiteflies, you will see a cloud of fleeing insects when the plant is disturbed. Whiteflies can weaken a plant, eventually leading to plant death if they are not checked. They can transmit many harmful plant viruses. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.
Possible controls: keep weeds down; use screening in windows to keep them out; remove infested plants away from non-infested plants; use a reflective mulch (aluminum foil) under plants (this repels whiteflies); trap with yellow sticky cards, apply labeled pesticides; encourage natural enemies such as parasitic wasps in the garden; and sometimes a good steady shower of water will wash them off the plant.
Pest : Aphids
Aphids are small, soft-bodied, slow-moving insects that suck fluids from plants. Aphids come in many colors, ranging from green to brown to black, and they may have wings. They attack a wide range of plant species causing stunting, deformed leaves and buds. They can transmit harmful plant viruses with their piercing/sucking mouthparts. Aphids, generally, are merely a nuisance, since it takes many of them to cause serious plant damage. However aphids do produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface growth called sooty mold.
Aphids can increase quickly in numbers and each female can produce up to 250 live nymphs in the course of a month without mating. Aphids often appear when the environment changes - spring & fall. They're often massed at the tips of branches feeding on succulent tissue. Aphids are attracted to the color yellow and will often hitchhike on yellow clothing.
Prevention and Control: Keep weeds to an absolute minimum, especially around desirable plants. On edibles, wash off infected area of plant. Lady bugs and lacewings will feed on aphids in the garden. There are various products - organic and inorganic - that can be used to control aphids. Seek the recommendation of a professional and follow all label procedures to a tee.
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.
MiscellaneousGlossary : Annual
An annual is any plant that completes its life cycle in one growing season.
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 : Shrub
Shrub: is a deciduous or evergreen woody perennial that has multiple branches that form near its base.
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.