Wednesday, June 20, 2012

Native Coneflowers-Challenges and Remedies

Native Coneflower Stands up to Challenges

Echinacea, Purple Coneflowers, are a heat resistant, drought tolerant native plant that is a staple in my garden. I have divided them around the garden for so many years, that I’m not sure of the cultivars anymore. 
100_0791 100_0792
Being a native, this group of plants has overcome threat from insects and diseases.  However, that does not mean that coneflowers don’t have some challenges. 
Insect pests that can affect coneflowers include caterpillars, Japanese beetles, grasshoppers, aphids,  mealy bugs, spittle bugs, and thrips.
grasshopper aphids on coneflower
Aphids are sucking insects that can weaken the stems.  Usually a firm spray of water from the hose will dislodge them. 
japanese beetle
Japanese beetles can chew a blossom to shreds in a very short time.  Hand pick them (I use gloves!) and pinch or drop them into a soapy solution.
Mealy bugs and spittle bugs are easy to spot.
The mealy bugs are soft-bodied wingless insects look like fuzzy cotton. They feed by inserting long sucking mouthparts, called stylets, into plants and drawing sap out of the tissue. Damage is minimal when only a few pest are present. However, at higher numbers they can cause leaf yellowing and curling as the plant weakens. Mealy bugs feeding is usually accompanied by honeydew, which makes the plant sticky and encourages the growth of sooty molds.
A strong water spray will dislodge mealy bugs, and is usually all that is needed.  If further control become necessary, spray with a soap/oil mixture if the water alone doesn't do the job. Mix 1 tsp. insecticidal soap, 1/2 tsp. horticultural oil, and 1 quart water in a spray bottle.
mealy bugs w sooty mold 
spittle bug2 spittlebug on aster
Spittle bugs suck!  Even though they look icky, the really do not do any harm to the plant. They hide in the bubbly secretions seen on plants.  Control of mealy bugs is using the water spray as well. Spray the underside of leaves where the spittle bugs hide. 
Other pests that attack coneflowers are rabbits and deer.  The young plants are often targets.
Some pests are not quite as obvious as the deer or rabbit.  The microscopic Eriophyid mites are such pests.  As these mites feed, the plant produces  tufts of growth on the flowers.eriophyid mites and tufts on blooms 
The mite will over winter in debris or the plant crown, and will infect subsequent years growth.  No controls are called for, but a plant can be removed to prevent spread of the mite. 

Other than insects, Echinacea can get a couple of diseases.  One is stem-rot.  This usually occurs when over-watering occurs, or the planting site does not drain well.  Compost added to the soil will allow water to drain, and will keep the roots of the coneflower from staying too wet. 
stem rot
The Aster yellows is a disease the is transmitted by insects, particularly leaf hoppers, or poor growing methods.  Aster yellows is a viral-like disease and is caused by a phytoplasma (previously called mycoplasma-like organism) and is spread by aster leafhoppers.The densities of aster leafhoppers, and incidence of the disease, can be strongly influenced by the occurrence of certain host weed species. These weed species include quackgrass, plaintain, chickory, knotweed, pineapple weed, stinkweed, wild asters, lambs quarters, sow thistle, ragweed, Kentucky bluegrass and wild carrot.
leaf hoppers
asters yellow disease   100_0798
Plants with Aster yellows have distorted, green flowers, and stunted growth. This one is in my garden, and I’m planning to dig it up and throw it.  Aster yellows is not treatable and spreads quickly. 
Black spot, a fungal disease is seen on coneflowers occasionally.  Black spot usually set up during, cool, moist periods. Powdery mildew can also infect coneflowers.
  blackspot on coneflower leaf For the most part, diseases can be prevented by utilizing proper cultural practices such as variety selections, plant and soil nutrition, irrigation and humidity management,  pruning, and row spacing. Air movement is key to reducing these fungal diseases.  Water only when needed, and avoid wetting the leaves.  Remove debris since the spores from these diseases can linger in the soil. 
Once black spot or mildew are observed, the steps to control them are less effective.  Pre-treat susceptible plants before the fungus are seen.  Mix 1 teaspoon vegetable oil, 1 teaspoon baby shampoo, and 1/3 teaspoon baking soda in 2 cups of water. This solution comes right from the kitchen! sum2007_compost_tea
Compost tea as a spray is a good option too.  In a five gallon pail, soak a scoop of compost for up to 24 hours.  Strain and spray. 
Echinacea is a long-lived perennial, and thrives in a sunny location.  Soil can be average to poor.  Plants have a  long taproot, to find moisture deep in the soil.  Hardy to Zone 3-8, coneflowers bloom for long periods during the summer. Many cultivars are being developed to extend the sizes and colors.
  Fancy Frills  Fancy Frills
Doopleganger Doopleganger

 double echinacea 'razamatazz' Razamatazz
Hot Lava Hot Lava
meringue Meringue
Echinacea is a native that has many attributes for the landscape.  Prairies or sunny borders, this plant holds it’s own. I feel the coneflower is definitely a keeper in my garden.
Thanks for stopping by today.  
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