Among avid gardeners, rue is considered a rare gem in the garden. Not only is this plant very versatile; it is also tough and undemanding, making it one of those plant species that are difficult to kill. In general, rue is not very fussy when it comes to its growth requirements, and can grow in almost any conditions or soil type without complaint. Most importantly, this perennial herb is hated by destructive pests and wildlife due to its strong aromatic scent, making it an excellent pest repellent in your garden!
But, despite all these great and resilient features, your rue plant may not always be in perfect health. Yes, it is drought- and disease-resistant, but it has one weakness that can quickly bring it to the brink of death – none other than the dreaded root rot! If you have been gardening for a long time, this disease is probably nothing new to you.
If you are wondering why your rue plant is dying, the likely culprit is root rot. Let us dig into the details below to help you understand how to rescue your dying plant.
Rue plant care overview
Rue, also known as Ruta graveolens or herb of grace, is an evergreen perennial known for its aromatic, bluish-green foliage. Its growth is similar to that of a shrub, reaching about 20 to 30 inches in height.
Since ancient times, rue has been widely used for culinary and medicinal purposes. Its branches were also used by Roman Catholics to sprinkle holy water over the heads of their followers as a sign of blessing, hence its nickname, “herb of grace.” However, in recent times, experts have issued warnings about using this heirloom plant for medicinal purposes, due to its toxicity.
If your aim is to grow rue as a host plant, then having it in your garden will bring a lot of benefits. Butterflies like the giant swallowtail, anise swallowtail, and black swallowtail favor this evergreen herb when laying their eggs. Caterpillars also love its leaves, leaving the plant bare for a short period. However, this sparse appearance will not last long as the leaves grow back quickly, making rue the ideal host plant to protect other, high-value crops or ornamentals in the garden.
One thing to keep in mind, though, is that rue might not be the best companion for all plants. Although it is great for repelling insects and destructive animals like deer and rabbits, it is known to produce chemicals in its roots that can cause stunted growth in certain herbs. You should therefore never plant it near other herbs like sage, basil, or mint.
So, what are the plant care requirements when it comes to growing rue?
Rue is considered a tough plant – it does not suffer from too many problems and is generally resilient against most pests and plant diseases. Aside from being an excellent host plant, a fully-established rue plant is also drought-resistant and does not need a lot of maintenance to thrive.
Rue typically grows in areas with hot and dry climates. It is considered hardy in zones four to nine, and is not as fastidious as some other garden plants. It can grow happily in poor soil, too, be it sandy or rocky. Hence, you will not need to spend money on special fertilizers to feed your rue.
Rue is also cold-hardy and should be happy and hassle-free in the ground until the first hard frost. Mulching is advised during the winter, however, to protect it from extreme temperatures.
Signs your rue plant may be dying
The most obvious signs of a dying rue plant are visible changes to the leaves. First, you may notice the leaves starting to wilt and turn brown or yellow. Their texture may then become crispy, and some parts of the plant might look soft or mushy. Overall, the plant will appear droopy and unhealthy.
Unlike most garden plants, rue is rarely harmed by pests and fungal leaf diseases. So, the most likely culprit to kill these plants is improper watering.
Why is my rue plant dying? The common culprit
Rue is one of those plants that are difficult to kill. Perhaps the only weakness of this versatile herb is its susceptibility to root rot, which is caused by too much water in the soil.
Root rot is a prevalent issue among overwatered plants. If you habitually pamper your rue with excessive watering, you are effectively drowning its roots in waterlogged soil and slowly killing the plant in the process.
Rue plants are drought-tolerant, and they would rather survive in a dry environment than sit in wet soil for too long. They really do not require very much watering; otherwise, their roots will not be able to absorb enough oxygen to keep them firm and healthy. Similar to other plants, their delicate roots can quickly start to decompose when exposed to watery soil and the soil-borne pathogens that come with it.
Once the roots are damaged, your plant will struggle with nutrient uptake. The nutrition from the soil will never reach the stems and leaves, and this is what causes the leaves to brown and wilt. Your plant will also stop growing, since it is no longer supported by the roots. Photosynthesis and other metabolic processes will be hindered as well. Slowly but surely, your favorite host plant will start losing its leaves and will eventually die.
To save your dying rue, stop watering it for as long as it takes for the soil to dry out. Keep in mind, however, that this method will only work for plants with minimal root damage.
For severe cases of root rot, you will need to uproot the plant and wash off the infected roots. Using a sterilized pair of scissors, cut off any roots that look dark and mushy. Roots that are firm and white are healthy, and should not be trimmed off. Once pruned, replant your rue in fresh soil.
How often should I water my rue?
As mentioned, rue prefers a warm, dry environment. It is not constantly thirsty and would be happy with sparse watering. Perhaps the only maintenance this plant needs is a deep and thorough watering once every three weeks or so – and that is it!
That said, you might need to adjust your watering routine according to your local weather conditions. So, stay up to date with the season and closely monitor your plant’s soil.
Since root rot is the number one enemy of rue, you need to make sure that you grow it in well-draining soil. For plants grown in containers, make sure that the pots have enough drainage holes for excess water to escape from. Also choose a potting mix that incorporates light materials to prevent compacted soil. Overall, your growing medium must be airy and light to prevent excess water from pooling.
If your rue is planted in the ground, you can add organic compost to ensure that the soil does not become compacted. Loosen the soil a little bit with a shovel and add organic materials like shredded leaves to improve soil aeration.
Despite their toughness and resilience, rue plants can also fall victim to root rot disease. To prevent this, check your soil regularly and never overwater your plants! Always keep in mind that these old-fashioned herbs are rarely harmed by drought, so they are more likely to survive underwatering than sitting in waterlogged soil.
Image: istockphoto.com / Andres Anibal nuñez cuello