Posted by Brent Wilson on 10/1/2017 to FAQ (Frequently Asked Questions)
So you purchased and planted a perfectly healthy shrub, tree, or other plant several or many months ago but now the ends of the leaves are turning brown or black or the leaves are dying and falling off the plant. What's the problem? There could be many causes for this but most often it has to do with soil moisture conditions.
If the soil is too dry the leaves on a plant that requires a consistently moist soil will often suddenly shock and fall from the plant.
If the soil is too wet; stays constantly soggy, the leaves on a plant that requires a well-drained soil will start browning at the tips and gradually die and either remain on or fall from the plant. The browning and dying leaves are a symptom of root rot, which is caused by too much water. Root rot can slowly kill a plant if irrigation is not modified or steps aren't taken to improve soil drainage.
Note: On every plant page in Wilson Bros Gardens you will find soil moisture needs under the Description tab and then under Plant Details.
In any event, if you suspect that the leaves on your plant are dying due to a soil moisture problem, and you are uncertain about soil drainage in the planting area, it's well worth taking the time to test the drainage.
How to test soil drainage:
1. Dig a hole 12" wide by 12" deep in the planting area, or very close to the root ball of a recently planted plant. If the hole fills with water you know for sure there's a soil drainage problem
2. If the soil is soggy looking or even dry, fill the hole with water and let it drain.
3. Then, after it drains, fill it with water again, but this time clock how long it takes to drain.
In well-drained soil the water level will go down at a rate of about 1 inch an hour. A slower rate indicates poor draining soil and is a caution, depending on the type plant and it's moisture needs, you need to improve drainage. A faster rate, such as in loose, sandy soil, may signal potentially dry site conditions and possibly a need to replant and add top soil and/or organic matter to the sandy soil to help retain moisture.
If after testing for soil drainage you find that the soil drains poorly, and the soggy soil conditions don't have to do with over-irrigation, steps will need to be taken taken to improve drainage in the area. This can be done two ways: either by lifting the plants and regrading the entire planting area or by replanting each plant in a raised mound, which raises the roots above the water table.
Below are instructions for how to plant a shrub, tree or other plant in a raised mound. If you feel the entire planting area needs to be regraded I suggest contracting with a local landscape contractor or grading company who uses a laser transit to ensure proper grade for sufficient water run-off and soil drainage.
Planting or Replanting In A Raised Mound
Note: Replanting is best done when a plant is in its winter dormancy stage. That said, if it's spring or summer and you fear your plant will not survive the soggy soil conditions until winter, go ahead and lift the plant to replant in a raised mound. Better to do that than to watch the plant die.
Start by digging up some top soil from elsewhere on your property that will be used to create the raised mound and place it in a wheelbarrow or on a tarp near the planting area. Alternatively, you can purchase native top soil from a local supplier.
Note: Though bagged top soil or other soil amendments can be added at a 25% ratio to the native top soil, avoid using these bagged amendments alone to build your raised mound.
Next, use a round point shovel to dig up the plant you will be replanting in the raised mound. Place your plant near the planting area, preferably in a shady area if replanting during summer.
Note of Caution: When moving your plant be careful to keep as much soil as possible intact around the roots.
Next, use your native top soil to fill in the hole from where you removed your plant and then to build a circular mound which at the center is equal to the height of the root ball of the plant and tapers gradually down to ground level, as shown in the illustration below. Tamp the soil as you build the mound.
Next, dig out a hole or depression in the center of the mound that is near to the size of the root ball of the plant.
Place the root ball of your plant in the hole at the center of the mound making sure the top edge of the root ball is level with the top of the mound. After setting your plant in the planting hole, use one hand to hold the plant straight and your other hand to begin back-filling your soil mixture around the root ball, tamping as you go to remove air pockets. Continue back-filling to the top edge of the root ball.
Note of Caution: To avoid suffocating your plant, avoid placing any soil on top of the root ball.
STEP 6 (Optional)
When planting in a location that is far from a water source, you can use remaining soil mixture to build a water retaining berm (catch basin) around the outside perimeter of the planting hole, as shown in the illustration above. This basin will help to collect water from rainfall and irrigation, but will not ensure the roots of the plant will receive enough water. Check soil moisture frequently in the raised mound until you know how long it takes to dry. Apply water as needed to the soil mound to keep the soil moist. Eventually your plant will grow roots down to the water table and will not require as much attention wot watering.
Next, deeply water the planting area, including the root ball. For an extra boost, to stimulate new root formation and stronger root development you can also water you newly replanted plant with a solution of Root Stimulator, which reduces transplant shock and promotes greener, more vigorous plants.
Spread a 2-inch layer of shredded or chipped wood mulch or a 3- to 4-inch layer of pine straw around the planting area to conserve moisture and to suppress weed growth. As the mulch decomposes it will add vital nutrients to the soil that your plant will appreciate. Avoid the use of freshly chipped or shredded wood for mulch until it has cured in a pile for at least 6 months, a year is better. Avoid placing or piling mulch directly against the base of your plant as this could cause the bark to rot.
You're done! Just remember to check soil moisture in the raised mound frequently and provide water as necessary to maintain a moist soil.
Hope this information was helpful. Don't hesitate to contact us if you have any questions or comments.
Plant Long & Prosper!
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