Rhodanthemum hosmariense ( Aster )

Spreading and bushy subshrub with soft, hairy, deeply-lobed silvery green leaves. Single flowers are formed with white florets and wide centers of yellow disk florets. Distinguished by its black margins on silver bracts. Blooms from early spring to fall. Easy to grow and will bloom throughout the year if deadheaded regularly. Susceptible to aphids and spider mites. Prefers moderately fertile, very well-drained soil in full sun.

Important Info : Sometimes referred to as Chrysanthemum hosmariense, Leucanthemum hosmariense, or Pyrethropsis hosmariense.

Google Plant Images: click here!

Free Garden Catalog

Characteristics

Cultivar: n/a  
Family: Asteraceae  
Size: Height: 0.33 ft. to 1 ft.
Width: 0 ft. to 1 ft.  
Plant Category: perennials,  
Plant Characteristics: low maintenance,  
Foliage Characteristics: small leaves,  
Flower Characteristics: showy, single, unusual,  
Flower Color: blacks, whites, yellows,  
Tolerances: deer, rabbits,  


Requirements


Bloomtime Range: Early Spring to Late Fall  
USDA Hardiness Zone: 9 to 10  
AHS Heat Zone: Not defined for this plant  
Light Range: Full Sun to Full Sun  
pH Range: Not defined for this plant  
Soil Range: Any  
Water Range: Normal to Moist  





Plant Care

Fertilizing

How-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.

Light

Conditions : Full Sun

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

Watering

Conditions : Moist and Well Drained

Moist and well drained means exactly what it sounds like. Soil is moist without being soggy because the texture of the soil allows excess moisture to drain away. Most plants like about 1 inch of water per week. Amending your soil with compost will help improve texture and water holding or draining capacity. A 3 inch layer of mulch will help to maintain soil moisture and studies have shown that mulched plants grow faster than non-mulched plants.

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.

Planting

How-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 : Pinching and Thinning Perennials

Once you plant a perennial, it does not mean that you will enjoy years of maintenance-free gardening. Perennials need to be cared for just like any other plant. One thing that distinguishes perennials is that they tend to be active growers that have to be thinned out occasionally or they will loose vigor.

As perennials establish, it is important to prune them back and thin them out occasionally. This will prevent them from completely taking over an area to the exclusion of other plants, and also will increase air circulation thereby reducing the incidence of diseases like botrytis and powdery mildew.

Many species also flower abundantly and produce ample seed. As blooms fade it is advisable to deadhead your plant; that is, to remove spent flowers before they form seed. This will prevent your plants from seeding all over the garden and will conserve the considerable energy it takes the plant to produce seed.

As perennials mature, they may form a dense root mass that eventually leads to a less vigorous plant. It is advisable to occasionally thin out a stand of such perennials. By dividing the root system, you can make new plants to plant in another area of the garden or give away. Also root pruning will stimulate new growth and rejuvenate the plant. Most perennials may be successfully divided in either spring or fall. Do a little homework; some perennials do have a preference.

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.

Problems

Pest : 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 : 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.

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.

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 : 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.

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 : Perennial

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

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.

Plant Images

Leave a Reply

Your email address will not be published. Required fields are marked *

*
*

This site uses Akismet to reduce spam. Learn how your comment data is processed.