A native of South Africa and Madagascar, the cape primrose (Streptocarpus spp.) sports fuzzy, dark green, ovate leaves. Clusters of five-petalled flowers appear throughout the growing season. This herbaceous perennial grows in U.S. Department of Agriculture plant hardiness zones 10 through 11, but will grow in any zone as a potted houseplant. It prefers full to part shade and fast-draining soil, and requires water only when the top 1 to 3 inches of soil are dry. The cape primrose may become wilted due to over-watering or lack of moisture. Once the foliage reaches this stage, immediate action to save the plant becomes vital.
Potted Cape Primrose
Insert your pointer finger into the top 1 inch of soil. Wiggle your finger back and forth very gently to determine whether the soil feels moist or dry.
Observe the pot's location if the soil feels moist to determine if adverse cultural conditions prevent the soil from drying. Move the pot if needed to position it in bright, indirect sunlight and an area with a constant daytime temperature of 50 to 70 degrees Fahrenheit. Leave the plant to sit until the top 1 to 3 inches of its soil becomes dry and its leaves fill out before watering it again.
Fill a cake pan half full of water. Place the potted cape primrose in the center of the pan immediately if the soil feels dry, allowing the water to begin soaking into the root ball's bottom. Refill the pan with water to keep the level even as the soil absorbs it.
Poke 1/2- to-1-inch-deep holes randomly in the top of the cape primrose's root ball with the end of a wire hanger. Fill a watering can with water. Pour the water slowly into the pot, directly on top of the root ball. Wait for the water to soak into the holes. Continue to pour water onto the root ball until the soil begins to expand and darken in color.
Move the pan containing the pot into a shaded location with a temperature of 50 degrees Fahrenheit to slow the leaves' water use. Let the plant sit in the water for one to two hours, refilling the water as needed.
Remove the cape primrose from the pan of water once the soil feels moist to a depth of 2 inches and the leaves perk up. Place it in bright, indirect sunlight, at a temperature of 50 to 70 degrees Fahrenheit, keeping it away from heating and cooling vents.
Garden Cape Primrose
Insert your finger into the top 2 to 3 inches of soil near the wilting cape primrose's base. Determine whether the soil feels dry or moist to discover if the plant requires water or not.
Do not water the plant if the soil feels moist. Wait until the soil dries to a depth of 2 to 3 inches and the leaves expand to their original appearance before watering. Cover the plant and its surrounding soil with a row cover or plastic tarp if it rains before the soil becomes dry. Remove the tarp as soon as the rain stops.
Pour water from a watering can or garden hose slowly onto the soil surrounding the plant if it feels dry. Wait for the water to soak into the soil. Poke holes in the soil around the plant's base with a wire hanger if the water runs off the soil's surface away from the plant. Pour water slowly onto the soil once more, allowing it to flow into the holes and penetrate the root zone. Add water to the soil until it feels evenly moist to a depth of at least 3 inches. Leave the plant for one hour, giving it time to soak up the water from the soil.
Check on the plant to see if its leaves look full and hydrated. Water the plant again if the foliage still shows signs of wilting. Repeat the watering and waiting process until the leaves fill out and return to normal.