Small Seedlings Everywhere means Self-Seeding.
Rose mallows like their rose of Sharon cousins, self-seed readily. Unwanted seedlings can be easily pulled if main plants are surrounded with mulch.
Leaves Curled, Discolored indicates Aphids.
Aphids are spindly-legged, pear-shaped insects little bigger than the head of a pin. Also called "plant lice," they attack tender branches and flower clusters. These pests suck sap from leaves and stems, causing the foliage to curl, pucker, and turn yellow, while reducing the shrub's vigor. Ants, attracted by the aphids' honeydew secretions, wander over the plants and protect the aphids from natural predators. Check under the leaves of hibiscus plants like rose mallow for small groups of aphids.
To dislodge light infestations, spray the undersides of the leaves vigorously with water three times, once every other day, in the early morning. Spray aphids with insecticidal soap every 2 to 3 days for heavier infestations. As a last resort, use pyrethrum spray, spraying it directly on the aphids. Take care to use pyrethrum late in the day to minimize killing honeybees and other beneficial insects that reside in your yard. Destroy nearby ant nests by breaking them open and pouring boiling water on them.
For more information see file on Controlling Aphids.
Holes In Leaves And Flowers seems to be Japanese Beetle.
Japanese beetles are especially attracted to flowers of the hibiscus family. Their grubs sometimes attack plant roots. Adults are 1/2 inch long, with shiny metallic green and copper-brown wing covers. Beetle larvae (grubs) are greyish-white, with dark brown heads. Fully-grown grubs are plump, 3/4 to 1 inch long, and lie in the soil in a distinctive arc-shaped resting posture. Where possible, handpick the beetles from the rose mallow plants and knock them into a pail of soapy water. Handpick stragglers not caught by the trap, knocking them into a jar of soapy water.
For more information see the file on Controlling Japanese Beetles.
Plant Weakens, Leaves Turn Yellow indicates Whiteflies.
Adult whiteflies, their presence clearly visible on leaf undersides, are white winged, moth-like insects about the size of a pinhead. In their pupa stage they are greenish white, oval and present in large numbers on the on the undersides of hibiscus leaves. Bump or brush branches of an infested rose mallow plant and they suddenly fly up, looking like flying dandruff. The whitefly causes yellowish mottling on the tops of rose mallow leaves. Nymphs and adults suck juices from plant leaves, buds, and stems. The sooty mold fungus develops on the honeydew secreted by immature insects. Spray visible whiteflies with commercial insecticidal soap spray every 3 to 5 days for two weeks. If that doesn't work spray them with pyrethrum every 5 days for two weeks as a last resort.
For more information see file on Controlling Whiteflies.
Reddish-brown Spots on Leaves means Scale.
Several kinds of scale insects sometimes attack rose mallow plants. They bore into the surface tissue of the leaves and twigs, causing telltale red spots on the leaves. White scale becomes evident when the leaf tissue is ruptured. Spray infested foliage and twigs with carbryl (Sevin) according to directions on the package.
For more information see file on Controlling Scale.
Leaf Spots Run Together; Exudates Seen indicates Bacterial Leaf Spot.
A bacterium sometimes infects rose mallow foliage, causing small, blister-like spots. They enlarge and run together. Ruptured spots release a bacterial ooze. In serious infections, plants may be defoliated and collapse. Remove and discard affected leaves as soon as spots appear. Dig up heavily infected plants along with the soil around their root ball and throw them in the trash. Keep the yard free of plant debris. Disinfect garden tools by spraying them with Lysol to prevent the spread of the bacteria. Spray affected plants weekly during rainy spells with a copper-based bactericide or Agrimycin. Control insects (such as aphids) that may transmit disease organisms. Increase air circulation by spacing plants more widely apart, and remove the lower 4 to 6 inches of foliage to avoid contact with wet soil.
Brownish-Orange Spots on Foliage, Stems means Rust.
Rust is caused by fungi that are parasites, requiring a host plant on which to live and carry out their life cycle. Sometimes they afflict rose mallow plants, causing brownish orange patches to appear on leaves and stems. Often rust can be ignored, but in cases where it is extensive, periodically spray a wettable sulfur solution on the affected tissues of the plants.
For more information see file on Controlling Fungal Disease.
