If you’re thinking of adding rhubarb to your garden, you may be wondering what kind of problems you can expect.
While rhubarb is generally a hardy plant, a few problems are common among gardeners who grow it.
These problems include pests, perennial weeds, and environmental stressors. Luckily, there are ways to combat these problems so you can enjoy fresh, homegrown rhubarb for years to come.
Common Rhubarb Growing Problems
Soil
Rhubarb thrives in well-drained soils that are high in organic matter. The soil where rhubarb will not grow well is typically sandy, with low clay content.
The ideal pH range for rhubarb is between 5.5 and 7.0; if the soil is too acidic or too alkaline, the plant will not thrive. In addition, rhubarb requires a high level of organic matter in the soil; if the level of organic matter is too low, the plant will not grow well.
Climatic Requirements
Growing rhubarb requires a climate that is cool and moist. It prefers temperatures below 38ºF during winters to break seed dormancy and properly germinate, eventually helping the plant flourish in the spring.
In the summer, temperatures below 73ºF are ideal for the growth of the rhubarb plant’s leaves, stems, and roots. It is not well suited for either hot and dry climates or extremely cold. It prefers full sun but can tolerate partial shade.
Crown Selection
Growing from crowns is known to be ideal for rhubarb farming. It is inexpensive and saves time and effort. However, selecting an incapable crown can trigger rhubarb growing problems.
You should avoid old, damaged crowns that don’t have a visible living shoot coming out of them.
Perennial Weeds
One of the significant rhubarb-growing problems faced by gardeners is perennial weeds.
They can compete with the plant for resources, including water and nutrients, which can lead to reduced growth.
Additionally, they can harbor diseases and insects that can infect the rhubarb plant and cause further damage.
Gardeners adopt mulching as the best method to control the spread of perennial weeds.
Rhubarb Diseases
Botrytis rot
Signs
The symptoms of botrytis rot are characterized by the presence of gray or brown lesions on the leaves.
These lesions eventually turn black and may be accompanied by mold formation on the leaves surface.
The affected leaves will eventually die and fall off the plant. In severe cases, the entire plant may be killed.
Control
The best way to control botrytis rot is by using a fungicide. There are many fungicides available, so it is essential to choose one specifically designed for rhubarb use.
Be sure to follow the instructions on the label carefully. Another way to help prevent this fungus is to ensure the rhubarb plants are not too crowded and have good air circulation.
Crown rot
Signs
The disease is often seen in wet, humid conditions or soils that are poorly drained. It is characterized by symptoms such as stunted growth, yellowing leaves, and wilting.
Earlier indications of the disease can be seen at the base of the leafstalks, where the crowns gradually turn brown and the rotting begins.
Control
To control crown rot in rhubarb, it is crucial to start with clean plant stock and avoid overhead watering.
In addition, choose a well-drained site with full sun for planting and mulch around the plants to help keep the roots dry.
If crown rot is present, remove and destroy infected plants and avoid planting in the same spot.
Downy Mildew
Signs
The symptoms of Downy Mildew fungi in rhubarb are characterized by the presence of yellowish-green to brownish-black lesions on the upper surface of the leaves. The undersides of the leaves are covered with a white, downy growth.
The lesions may eventually coalesce and cause the leaves to wither and die. In severe cases, the stems may also be affected.
Control
Choose a planting site that has not been affected by past attacks of this disease. Infected crowns should be removed and burned immediately to stop the spread of this disease to other plants in your garden.
You can also use a fungicide, but it should be your last resort to control this problem.
Leaf Spot
Signs
The most common symptom of leaf spot is the presence of small, dark spots on the leaves. These spots are usually circular and may have a yellow or brown halo around them.
Control
It is essential to practice good cultural practices to control leaf spot disease in rhubarb. This includes avoiding overhead watering, which can spread the disease. Instead, water at the base of the plant.
It is also important to remove and destroy any infected leaves. Finally, using a fungicide labeled for leaf spot on rhubarb can help to prevent and control the disease.
Rhubarb Pests
Rhubarb Beetle
Signs
The signs of a rhubarb beetle attack include chewed leaves, holes in the leaves, and skeletonized leaves. The larvae of the beetle feed on the underside of the leaves, and the adults feed on the upper side of the leaves.
It can also attack the crown as well as the roots of the plant.
Control
The easiest way to control rhubarb beetle attacks is to pick the beetles off by hand and destroy them.
You can also try using a vacuum cleaner to remove them from the plant. If the infestation is severe, you may need to use an insecticide.
Rhubarb beetle attack can also be controlled by destroying the larvae before they have a chance to mature into adults. This can be done by tilling the soil around the plant or using a larvicide.
Badly affected parts of the plant shall be disposed of to stop the reach of this notorious pest from reaching other plants in your garden.
Rosy Rustic Moth
Signs
They attack plants that are young and weak. In most cases, it damages the rhubarb leaf stalks making the plant unfit to sell in the farmer’s market.
Control
The attack can be controlled through cultural, biological, and chemical control.
Cultural practices include crop rotation, early planting, and late harvest. Biological control involves the use of predatory insects. Chemical control consists of the use of insecticides and fungicides.
Monitoring the field and eradicating the weeds where the pest lays eggs are also crucial to control the problems.
Slugs and Snails
Signs
They feast on the leaves of the rhubarb plants. The symptoms of their attack are evident in the presence of ragged holes in the leaves. If left unchecked, they can quickly decimate a plant.
Control
A few things can be done to control slugs and snails’ attacks on rhubarb. One is to ensure that the area around the rhubarb is clear of debris and leaves, as these provide hiding places for the pests.
Make sure that the crowns you are planting are not infested with slugs and snails.
Another is keeping the soil moist, as dry conditions may cause the slugs and snails to seek other food sources.
Finally, you can use a variety of baits and traps specifically designed to control these pests.
Loopers
Signs
The most significant sign is the presence of tiny, green caterpillars on the plant’s leaves.
These caterpillars are the larvae of the looper moth, and they feed on the leaves of the rhubarb plant, which can eventually kill the plant.
Other signs include chewed leaves and webbing on the plant.
Control
One way to control loopers’ attack on rhubarb is to prevent them from gaining access to the plant in the first place.
This can be done by covering the plant with a physical barrier, such as a piece of cloth or netting. Another way to control loopers is to remove them from the plant manually.
