A: Go about 6-8 inches deep and take several samples from around the root area placing the samples in a bucket. Mix the soil and bring us one sample – about a cup is fine. Master Gardeners man the Yulee satellite office on Fridays 10am – 2pm and can run a pH for you at no cost. Call us at 904 530-6351 for directions to the Yulee satellite office. You can also drop the sample through the letter box on the door and we can run it anytime during the week.
Now, just a few things other things to consider regarding your gardenia shrub:
1. Gardenias should not be planted by the foundation of a home or near the sidewalk, driveway, or walkways as these concrete structures leach and have a tendency to raise the pH to uncomfortable levels for these acid loving plants.
2. Planting them under the eaves of the house encourages leaching too and often the plant will get too much water off the roof if there are not gutters. Too much water can create the prefect environment for disease such as fungal leaf spots and root decays.
3. Some cultivars of gardenia do better with morning sun exposure and afternoon shade.
4. Keep lawn grass as far away from any tree or shrub as the things we do to lawn grass we should not do to trees or shrubs. Be careful about applying lawn grass weed killers around the roots of trees or shrubs.
5. Keep mulch off the trunk or any tree or shrub. Allow for an area around the base of the trunk which contains only soil and air. Mulch should be only 2-3 inches deep. Never use rock as it can compact the soil and retains heat – neither is good for trees or shrubs. Pine products are preferred.
6. It is critical to ensure the shrub is not planted too deeply. You should be able to find the large roots coming off the trunk in just an inch or so of soil. More than a few inches of soil on the roots is too deep.
7. Watering the shrub twice a week like the lawns can be excessive and they hate it.