Croton Is Dying
Croton will display many signs of distress when it is growing in the wrong conditions. Some symptoms are easily remedied, such as dull or faded leaves. Both of these issues can be solved by changing the position of the plant. Too much shade will cause the leaves to turn green, while too much heat will cause the leaves to lose their natural shine. Position Croton in indirect bright light for at least 4-5 hours a day with protection from hot afternoon sun. Leaves that are curling also indicate that the plant is receiving too much light and possibly too much fertilizer.
Just like other large-leaved tropical plants, Croton will drop its leaves from time to time. Generally, this is not something to be concerned about. A Croton may drop its leaves if moved from one location to another. Once the plant has acclimated to the new location, new leaves will grow back. Leaf drop can also indicate overwatering or underwatering. Croton requires consistently moist soil while actively growing during the spring and summer. Although this plant is a short-lived tropical houseplant, diseases and pests rarely do lasting damage.
Croton Leaves Turning Yellow
The leaves of Croton may turn brown if temperatures or humidity levels are too low. If the plant is too close to the heating or air conditioning vents, the tips may brown first. Insufficient watering during the growing season also causes browning of the leaf tips. To remedy this, use a fine mist sprayer to raise the humidity around the plant and water the plant consistently. If the leaves turn brown along the edges, the temperatures may be too cold for Croton. Move the plant indoors if it is growing on a patio or deck for the summer. Indoors, ensure that your Croton is not near air conditioning vents, fans, or uninsulated windows (during the winter).
Croton are susceptible to two major pests: scale insects and spider mites. Both pests are more common on plants that are moved outdoors for the summer and grown inside during the winter months. Quarantining your houseplants before bringing them in for the winter helps to pinpoint and treat any potential pests before they can enter the house. Both spider mites and scale insects are easily transmitted to other houseplants, although early detection typically prevents any major damage.
Photo by Scot Nelson
Spider mites most often attack when either the humidity is very low indoors or the weather is hot and dry outdoors. The extremely small spiders can be black, brown, or reddish in color and often are not noticeable until they begin to spin cottony webs in between the leaf and stem nodes of the plant. Spider mites suck sap from plant leaves, causing a stippled or yellow streaking of the foliage. Plants that are overfertilized can encourage infestation, but the humidity levels also need to be low for Spider mItes to survive. Spraying the plant with a sharp stream of water from a hose outdoors may clean most of the mites and webbing from the plant. Concentrate the spray on the undersides of the leaves and in the leaf nodes where the mites spin their webs. Avoiding high nitrogen fertilizer will also keep plants healthier and able to fend off any attacks. Keep Croton well watered and do not allow the plant to dry out during the growing season.
Scale Insects are most likely to infect plants that are heavily fertilized. These sap-sucking insects are green, brown, or silvery in color and very flat. They attach to the undersides of the leaves and in the leaf and stem nodes. As they feed and reproduce they also exude a sticky liquid that is clear and can result in a secondary infection of sooty mold or ants (especially while the plant is outdoors during the warmer summer months). The Scale insects are easily wiped off the plant with either a gloved finger or a cotton pad wetted with isopropyl alcohol. The alcohol kills the insects on contact but does not harm the plant when used occasionally. Treatment may need to be done every few days for a couple of weeks to disrupt the lifecycle of the insects. Heavy infestations of Scale may require heavy pruning of affected branches. Dispose of this plant material in the trash or burn it. Composting in a home composter is often ineffective at killing pests.
Photo by Scot Nelson
The common diseases of Croton are Anthracnose, a fungal leaf spot disease, and Crown Gall, which is a bacterial infection of the roots or stems of the plant. Often Crown Gall is apparent on the plant when you bring it home from the nursery or garden center. Crown Gall bacteria are passed between plants during propagation through stem cuttings or using infected pruners to groom and shape plants. The galls show up as fleshy or corky-looking growths on the base of the plant where the roots meet the stems. Sometimes the galls will be visible further up the stem where it joins with a leaf node. The infected soil should be discarded and not reused for other plants. Remove infected stems or leaves with a sharp knife or pruners. Disinfect the blades in between each cut so as not to reinfect the Croton. If galls are seen on the roots, dispose of the plant altogether. Plants that are still in decline after treatment should be discarded.
Anthracnose in Croton appears as black or brown spots on the upper and lower sides of the leaves and stems. Plants watered with overhead sprinklers or exposed to heavy rains are more susceptible to infection. Fungal leaf spot travels by water or moisture across a plant or onto surrounding plants. Using soaker hoses or drip irrigation for outdoor-grown Croton will help to keep the foliage dry. Provide plenty of space between plants to allow good air circulation. Remove any affected foliage as soon as possible to keep the fungus from spreading.
Croton Is Not Blooming
Croton grown as a houseplant doesn’t typically bloom. The flowers are inconspicuous and typically develop when the plant is mature. Some varieties will bloom in 3-4 years, others could take as long as 10 years. Providing the proper growing conditions and keeping your Croton healthy is the best way to prepare your plant to flower. Keep the potting mix consistently moist during active growth in the spring and summer. Do not place your Croton in a location that is drafty or cold during the winter months. Fluctuations in temperature can cause leaf drop, which in turn forces the plant to put energy into replacing the dropped foliage instead of developing flower spikes. Fertilize Croton with a diluted liquid fertilizer or slow-release granular feed that has an NPK ratio around 3-1-2 once a month from March to September. Reduce watering during the winter months when growth slows to reduce the chance of root rot.
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