Tired of seeing those bare patches on your lawn or under the trees in your backyard? Then planting pachysandra might help you improve the aesthetic of your outdoor space. These shade-loving evergreens are well known for their rich green, lush foliage, making them the ideal plants to carpet the shadier parts of your garden.
If you are already growing pachysandra plants, it can be unsightly – not to mention alarming – if they suddenly start turning yellow. This discoloration is generally a red flag and should thus not be taken lightly. Improper watering, pests, nutrient deficiency, and inappropriate soil pH are the leading causes of yellowing pachysandra leaves. Thankfully, though, you can correct these issues with early intervention and proper care. All the details are further explained in this guide.
Pachysandra plant care overview
Pachysandra is an evergreen perennial that is commonly used as ground cover in hard-to-plant areas. This dwarf shrub can really spread out nicely, like a dense, dark-green carpet, and is known to adapt well to dry, shady areas, particularly beneath tree canopies, on shady slopes, or in shrub beds. This perennial also produces individual pistillate flowers that, although not showy at first glance, are quite interesting upon closer inspection.
Pachysandras require proper spacing to grow well – ideally about nine to 12 inches between plants. Replenishing the planted beds yearly with organic matter and fertilizers is also important to keep them lush and green.
These herbaceous evergreens prefer slightly acidic and moist soil to help them grow into a dense landscape cover. When planting your pachysandra for the first time, keep in mind that the young plants will need constant watering until their roots have become fully established.
Under normal weather conditions, mature pachysandras only need to be watered once a week. During dry seasons, it is recommended to give them a good soak of about one inch of water, rather than light sprinklings. Although these groundcover plants are drought-tolerant, keeping their soil consistently moist will help them spread faster.
Pachysandra yellowing leaves – common causes and fixes
Any gardener knows that yellowing leaves on their plants is usually a sign of trouble. There are many possible reasons your pachysandras might suddenly display unhealthy-looking foliage. Check out the common causes and fixes below to learn how to revive your ailing plant:
1. Too much sunlight
Sunlight is essential for plants to carry out photosynthesis, which is the process responsible for keeping their foliage lush and green. But, as the common saying goes, too much of a good thing can be harmful, rather than helpful – and prolonged exposure to full direct sunlight can cause irreversible damage to your plants. At first, the leaves might turn pale green, and then gradually transition to yellow until they die and fall off.
Pachysandras are shade-loving plants that cannot tolerate the intense heat of the sun – the ultraviolet rays can quickly bleach or burn their leaves. To fix this issue, simply move your pachysandra to an area with partial shade.
2. Waterlogged soil
Waterlogged soil is an enemy of most plants. The condition is undesirable because it drowns the roots and inhibits the plant’s nutrient and oxygen uptake. Moreover, overly saturated soil can promote the growth of fungal spores that will attack the compromised roots, thus hastening the death of your lovely evergreens.
There are several ways to fix or avoid waterlogged soil. For starters, you need to stop overwatering your plants. Pachysandras usually only require once-weekly watering. Keep in mind that the fully-established plants are also drought-tolerant, meaning they will have a better chance of surviving underwatering than overwatering.
Another important factor to check is the type of soil used. If your pachysandras are planted in compacted or clay-like soil, they will likely struggle with standing water. The solution is to provide a ditch for your groundcover plants, to quickly drain any excess water. You can also consider transplanting your pachysandras into another soil with better drainage and aeration.
3. Lack of iron
Iron is an important micronutrient for the pachysandra’s leaves. It plays a role in the plant’s metabolic processes, including the synthesis of chlorophyll. Without sufficient amounts of iron, plants cannot grow properly or healthily. Iron deficiency also makes your evergreens susceptible to iron chlorosis.
In most cases, adding chelated iron powder or blood meal into the ground should solve the iron deficiency for your plants. You might also need to check the pH level of your soil, as this can affect their ability to absorb nutrients.
4. Soil pH is too high
As mentioned above, the wrong pH level can compromise plants’ absorption of essential micronutrients available in the soil. For pachysandras, the optimal pH range is between 5.5 and 6.5. In other words, these shrubs need slightly acidic soil to thrive.
However, if the pH level is too high, the plant will not be able to absorb nutrients, no matter how many fertilizers or supplements you add to the soil. The result is a nutrient-deficient pachysandra, hence the yellowing of all its foliage.
To solve this issue, you might need to consider purchasing a pH test kit to check the soil’s pH level. If the pH is too high, you can remedy it by adding milled sphagnum peat to bring the pH down to its correct values. You can also consider other chemicals like sulfuric acid or aluminum sulfate to effectively reduce the soil’s pH.
5. Root-knot nematode infestation
Yellowing leaves alongside other symptoms like wilting, stunted growth, and defoliation might also indicate a pest infestation. Root-knot nematodes are one of the several minute pests that can affect your pachysandras. These worm-like organisms attack the root system of the plant, causing distortions and knots or galls on the affected roots.
One of the most effective ways to beat the infestation is to apply liquid fish emulsion to the soil to keep the nematodes off your plants. Also consider adding more compost to the soil, specifically leaf mold, to attract beneficial fungi that can kill the pesky nematodes.
6. Spider mite infestation
Spider mites are a common enemy in the garden. Pachysandras struggling with spider mite infestation tend to have visible webbing on the leaves that looks like spider webs. If you do not act quickly, these tiny enemies can quickly destroy the health of your plants. Spider mites feed on the plants’ leaf sap, causing the leaves to turn yellow and become distorted.
To deal with a spider mite infestation, first dislodge the insects from the leaves by spraying them with a strong jet of water from a garden hose. Next, spray the leaves with diluted insecticidal soap to kill the remaining pests. You can also mix water and 70 percent rubbing alcohol to eradicate the mites. Simply dip a cotton swab into the alcohol mixture and use this to wipe the affected leaves and instantly kill any visible pests. Repeat the steps every four to seven days until your pachysandras are pest-free.
7. Scale infestation
Pachysandras are susceptible to scale infestation, too. Yellowing leaves may be an early sign of this, and can be followed by stunted growth, drooping, defoliation, and overall loss of vigor. To make the situation worse, these pests also excrete a honeydew-like substance on the leaves’ surface that attracts ants and sooty mold.
Scales look like little bumps on your plants’ leaves, with rounded, waxy shells. Their bodies can be yellow, brown, white, or black, and range from one tenth to two fifths of an inch in diameter. Like most pachysandra pests, scales suck the sap from the stems and leaves, leaving visible damage on your plants.
Here is one quick solution to get rid of the scales. First, rub the affected leaves with cotton dipped in soapy water or 70% rubbing alcohol to remove the pests. Next, spray your plants with horticultural oil to suffocate the remaining scales in their shells. You can also prune off the damaged branches or leaves. Once you have applied these remedies, check on the progress of your plants every few days. Repeat the treatments until all the pests are gone.
Pachysandra leaves can turn yellow for various reasons. To bring back the lush green color of your favorite ground cover, you will need to identify the underlying issue and then address it right away. Hopefully, with the lessons learned during this process, you can prevent the same foliage problem in the future!
Image: istockphoto.com / krisblackphotography