Can Mosquito Repellent Grass Really Repel Mosquitoes? Scented Geranium Growing Methods and Precautions

Mosquito repellent scented herb, also known as mosquito repellent grass or scented geranium, is a perennial evergreen herbaceous plant with very strong vitality. It can be grown in courtyards and indoors in both northern and southern homes, so can mosquito repellent grass really repel mosquitoes? What are the growing methods and precautions?

Mosquito repellent grass, scientific name Pelargonium graveolens (scented geranium). Perennial herb, shrub-like, can reach 1 m in height. Stems erect, 80-90 cm tall, grayish green, woody at the base, fleshy above, densely covered with glossy soft hairs, fragrant, with very strong vitality. Leaves have long petioles, broadly cordate-ovate, 5-7 palmatifid, the lobes further divided, the lobules serrate at the margins; flowers small, densely borne in small umbels, opposite the leaves, the whole plant can be steam-distilled for aromatic oil, often cultivated as an aromatic plant. Because of its fragrance, it is often grown as a potted ornamental. Native to South Africa.

Is mosquito repellent grass useful?

The answer is yes, and there is still no conclusive proof that the fragrance given off by aromatic plants such as mosquito repellent grass and night-blooming jessamine is harmful to human health, so it can be grown with peace of mind. When the plant is 30 cm tall with 40 leaves, the mosquito repellent effect is at its best.

Mosquito repellent grass can be shaped into a bonsai, often placed in offices, living rooms and business premises (restaurants, hotels) to purify the environment, delight the eye, and be both attractive and practical. Mosquito repellent grass gives off a lemon fragrance year-round, blending the aromatic substances of geranium and lemongrass, filling the air with fragrance, freshening the air, and safely repelling mosquitoes. It is a completely natural mosquito repellent product with no toxic side effects whatsoever.

I. Growing methods for mosquito repellent grass

1. Soil

Mosquito repellent grass prefers neutral to slightly acidic soil. Within 6 months, use a special self-mixed nutrient soil of 6 parts peat soil, 1.5 parts vermiculite, 1.5 parts perlite and 1 part coal ash, with a pH that is slightly acidic to neutral. You can also buy a ready-mixed foliage plant substrate soil (pH 5.5-7). After six months, mosquito repellent grass is extremely adaptable and can be grown in any soil. A two-year-old mosquito repellent grass has a woody main stem and can be pruned, and shaped in the soil as you like according to personal preference.

2. Temperature

Mosquito repellent grass likes warmth, with 10 to 25°C being the suitable growing temperature. Temperatures below 7°C or above 32°C are unfavorable for growth. The indoor overwintering temperature should not be lower than 12°C. Above 15°C it can normally give off its lemon fragrance, and the higher the temperature, the stronger the fragrance. Spraying a suitable amount of water mist on the leaves of mosquito repellent grass can make the citronellal substances release continuously, thus making the mosquito repellent effect even better.

3. Light

Mosquito repellent grass likes shade and cannot tolerate strong light during growth. Especially in summer, shading must be strengthened, and it can be planted under trees or in shaded places. Household potted plants are generally kept indoors for cultivation.

4. Watering

After repotting, mosquito repellent grass should be watered once. Normally water thoroughly once every 3-6 days, but do not let water accumulate. Watering should follow the principle of alternating dry and wet. Water when the surface of the potting soil turns white. In summer, when temperatures are high, water less, watering thoroughly once a week. From July to August, spray water frequently to cool it down and keep the surrounding environment of the mosquito repellent grass moist.

5. Fertilizing

Start fertilizing 10 days after the seedlings recover. Spring and autumn are the vigorous growth periods of mosquito repellent grass, and it is generally fertilized once every 15-20 days. In early April, after mosquito repellent grass grows new branches, apply a dilute organic liquid fertilizer once a week. In late April, move it outdoors, and mosquito repellent grass will bloom one after another. In summer, when temperatures are high, water less and do not fertilize, which helps the root system of mosquito repellent grass develop well and improves disease resistance. For home growing, a small amount of cake fertilizer and rice-washing water can also be applied.

6. Pests and diseases

Diseases caused by improper management include root rot or stem and leaf rot, followed by leaf shrinkage and black spots, and then the whole plant withering. This is caused by too much humidity, too high a temperature, and at the same time poor ventilation or excessive seedling density. Fungicides such as chlorothalonil or carbendazim (800 to 1000 times dilution) can be sprayed. But do not spray frequently.

II. Care methods for mosquito repellent grass

1. Propagation method: usually by sowing or cuttings; cuttings root easily in spring and autumn. Cuttings are the main method, and tissue culture can also be used. In April and May or September and October, cut sturdy branches with terminal buds, 5-8 cm long, let the cut surface dry, then insert them for rooting, keeping 2-3 terminal buds. Shade and keep moist; roots will form and the plant will survive in about 15-20 days. When breeding new varieties, artificial pollination is often used, and then seeds are collected and sown, germinating and emerging in 7-10 days at 20°C.

After the cuttings grow new leaves, they can be potted, using a neutral culture soil as the potting soil and giving sufficient light. During the growing period, top-dress once every 10 days. Follow the principle of “do not water if not dry, water thoroughly when watering”. In the high-temperature season of July-August, the leaves turn yellow, showing that the plant has entered a dormant state; at this time place it in a cool, ventilated place and protect it from rain. In autumn, when the climate turns cool, the plant regains vitality and enters the growing and flowering period again; at this time cut off the withered and yellow branches and leaves and carry out normal water and fertilizer management. In late autumn, move it into a low-temperature greenhouse for care, with an overwintering temperature above 5°C. With proper care, it will bloom as usual, and long-day conditions are favorable for flower bud differentiation and flowering. Spring cuttings can bloom by autumn, while autumn cuttings can only bloom in early summer of the following year; repot in autumn after the flowers fade.

2. Transplanting: select robust 1-year-old branches with short internodes and insert them in a seedbed for centralized seedling raising, then transplant them into the field. This method is generally used in areas with heavy winter frost, using small cold-proof arches or covering with weeds to help them overwinter safely; after the late frost of the following year, they can be lifted from the nursery and planted in the field.

3. Hydroponic method

① Select a robust branch and prune it. Choose a diagonal cut, which can increase the area of the cut surface exposed to water. Then cut off the lower leaves, keeping a few leaves at the top.

② Drill a small hole in the foam of a size matching the plant's thickness, then insert the mosquito repellent grass branch. Pour a certain amount of water into the hydroponic container, then place the mosquito repellent grass branch into the hydroponic container. The foam board can not only fix the plant but also reduce water evaporation. In addition, note that the length of the mosquito repellent grass branch submerged in water should not be too long. It is recommended to disinfect the hydroponic bottle before use.

③ Change the water every four or five days. When changing the water, pay attention to cleaning and disinfecting the hydroponic container. In addition, to ensure the health of the hydroponic branches, also promptly clean off any rotting or secreted substances and leaf and branch tissues on the branches. You can occasionally spray a little water on the leaves of the branches. For the hydroponic water, it is recommended to use purified water, or you can add a little nutrient solution to it.

④ With proper daily care, generally in about 15-30 days, you can see the mosquito repellent grass rooting. Once the roots look healthy, you can transplant it promptly. In the first week after potting, it is not recommended to place it in the sun. Wait until the plant grows new leaves; at this point you can be sure the mosquito repellent grass is growing very healthily, and then it can be placed outdoors to receive sunlight.

4. Care precautions

① Sudden leaf drop in a short period is often caused by too large a temperature change or insufficient light. Leaves turning yellow and soon falling off are mostly caused by insufficient light and excessive watering. This phenomenon can also occur when the winter temperature is too low.

② Dry leaf tips or scorched leaf margins are sometimes due to excessive light or dry air, and sometimes caused by excessive fertilizing or dry potting soil. Spindly, overgrown branches and leaves are mainly due to insufficient light, excessive nitrogen fertilizer and improper watering; move it to a place with light and prune the branch shape.

③ Yellow or brown patches on the leaves that look like water stains may be the result of overly forceful watering, with mud splashing onto the leaves and then being exposed to strong sun.

④ Mosquito repellent grass grows fast and needs repotting once a year to add soil and fertilizer, usually from February to early March in early spring. First prune heavily, leaving only 3 lateral buds at the base of each branch, then remove it from the pot, pull away the old and decayed roots around it, and replace with new fertilized culture soil and apply base fertilizer.

⑤ After new branches emerge in early April, apply a dilute organic liquid fertilizer once a week; in late April, move it outdoors and it will bloom one after another.

⑥ In early June, move it to a spot with scattered light on the inner side of the balcony. For courtyard care, move it under tree shade, on the east side of the house, or under a shade shed. Note that when the surface of the soil in a small pot turns white, or when the soil 1 cm below the surface in a large pot feels moist, water it.

⑦ In the high temperatures of July to August, spray water frequently to cool it down and keep the surrounding environment moist; do not let water accumulate in the pot. Move it indoors before the early frost arrives in mid-October. In winter, keep the room temperature not lower than 12°C, with sufficient light and fresh air, and it will bloom continuously. For professional cultivation to supply large quantities of flowers for the “May Day” holiday, it can be heavily pruned in late autumn, moved into a low-temperature room (below 10°C), kept with sufficient light, watered in a controlled manner to maintain moisture, and cared for with moderate ventilation.

III. Precautions for growing mosquito repellent grass

1. When mosquito repellent grass is 30 cm tall with 40 leaves, the mosquito repellent effect is best. If yellow leaves appear on the mosquito repellent grass, they need to be removed promptly.

2. During the day, do not let mosquito repellent grass receive direct sunlight; overly harsh sunlight will make the surface of the mosquito repellent grass scorched yellow. It is best to place the mosquito repellent grass on the balcony and just keep the soil moist.

3. After the mosquito repellent grass grows larger, give it a larger pot. The root system of mosquito repellent grass is quite well developed and can absorb many minerals from the soil.

4. If mosquito repellent grass is not managed properly, it will cause root and leaf rot, followed by black spots on the leaves and the whole plant withering. This is caused by watering too much and lack of ventilation. You can spray a little chlorothalonil solution and quickly move the mosquito repellent grass to a ventilated place for growing.

5. The common short-term leaf drop is generally caused by insufficient light for mosquito repellent grass; you can appropriately place the mosquito repellent grass in a place with light for growing. The leaves of mosquito repellent grass falling off and turning yellow are due to lack of water. In winter, this condition may also be due to too low a temperature. Excessive fertilizing or overly strong light can also cause the leaves to scorch yellow, so attention is needed.