My Trumpet Vine Has Black Leaves

Growth Habit

• Trumpet vine is a fast-growing plant that leaves some dead foliage and stems behinds as it quickly stretches. It can grow 10 feet a year, reaching a full length of 30 to 40 feet and can sometimes stretch as much as 2 feet a week. New foliage grows on top of the old, which then turns brown. Removing these old branches improves the vine’s appearance and prevents moisture or pathogen buildup. Regularly remove the brown foliage left behind.

Spots on Leaves

• Fungi including Cercospora and Phyllosticta can cause leaf spot conditions with areas of dying leaf tissue that vary in color and size. High moisture and humidity levels can make this a serious problem. Removing dead foliage from around the plant controls the problem. Treat the plant with fungicides containing chlorothalonil or thiophanate-methyl. Although not technically a leaf spot disease, some blight diseases cause sections of browning foliage. Blight caused by the bacterium Mycosphaerella tecomae can leave angular, brown patches on foliage.

Rot Conditions

• Dying foliage and necrotic leaves might indicate a serious condition such as root rot. The trumpet vine is susceptible to a Phymatotrichum root rot, which is caused by the fungus Phymatotrichopsis ominvorum. Plants with this disease may have sections that turn brown and die off, leaving behind an area of mold in the soil. There are no fungicides for with this disease. Avoid planting new plants in the soil nearby prevents further infection. Rotating crops and enriching the soil boosts levels of microorganisms that compete with this particularly fungus. A vine with black, dying foliage may also indicate a fungal infection that causes wilting, such as Verticillium wilt. This disease is caused by Verticillium albo-atrum and V. dahliae fungi, which affect many plants including the trumpet vine. It can cause yellowing, wilting leaves. There are no chemical treatments available, but removal of weeds and extra watering can help.

Proper Care

• Pinpointing the particular pathogen infecting the trumpet vine is difficult, but basic care improves the plant's health and reduces the emergence of black leaves. Too much water can often create conditions that cause leaves to die off early. The trumpet vine is drought tolerant and does best in a slightly dry environment. Removing dead foliage from around the vine prevents a moist environment that encourages fungi. Providing full-sun exposure encourages a vigorous plant and dry conditions.