All Gardenia varieties, including the dwarf 'Prostrata' cultivar, demand organic, fertile soil that is acidic while remaining light and easy-draining. When gardenias don't get the soil they expect, performance can be sub par with the incompatibility manifesting itself in other unpleasant symptoms. Yellowing chlorotic leaves, root rot, weak branch growth or diminished flowering can all be traced to unbalanced or inappropriate soil conditions. Improving the soil at planting and hewing to cultural practices that maintain or build the quality of the soil will help the trailing dwarf gardenia to thrive and perform well, over time. Till up a planting area in full sun, partial or filtered shade. Till 3 to 6 feet of soil area for each dwarf gardenia to be planted. Loosen the soil, break up or remove dirt clods, stones, old plant roots and any other debris on or in the soil. Amend nutritionally weak soils with 1 to 2 lbs. per plant of compost and well-aged livestock manure for each plant. Amend heavy or clay soils with 1 to 2 lbs per plant of coarse sand and coarse compost to improve drainage and tilth. Till in the amendments to a depth of at least 10 inches. Correct alkaline soil with elemental sulfur to boost the acidity and lower the soil pH to below 7 pH. Apply according to label directions. Conduct a soil test if there are doubts about the make up of the planting soil. Till in the sulfur to a depth of at least 10 inches. Add a product label recommended dose of organic, slow-release fertilizer to the planting soil of acid-loving plants. Choose a product with a guaranteed analysis of 4-6-4 or a similar ratio. Do not add chemical fertilizers to the planting soil as this can burn the roots. Till the fertilizer into the top 6 inches of soil. Water the prepared soil to drench it at least a 5 inches deep to hydrate the soil and amendments, and to mix the nutrients in the soil. Plant the gardenias the next day when the soil is moist but no longer wet. Water the gardenias in after planting.