How to Grow Pentas & Lantana Together

Remove weeds, rocks and other debris from the planting site. Spread a 3- to 4-inch-deep layer of compost over the planting site with a rake. Mix the compost into the top 8 to 10 inches of soil with a garden fork or rototiller.

Dig holes in the planting site with a trowel. Make each hole twice as wide and equal in depth to the corresponding plant's root ball. Space holes for individual pentas 18 to 24 inches apart. Space holes for the lantanas 4 to 6 feet apart, depending upon cultivar. Position the holes for lantana cultivars that have taller mature heights than the pentas towards the back of the planting site, to avoid blocking the smaller plants.

Place one plant in the center of each hole, grouping the pentas together and the lantanas together. Backfill each hole with soil, tamping it down around the root balls. Do not overfill the holes or bury the plants deeper than they were previously growing. Water the area thoroughly with a garden hose.

Water the plants when the top 1 to 2 inches of soil becomes dry. Apply water from a garden hose directly to the ground. Water the plants during the morning hours only, allowing plenty of time for the moistened foliage to dry before night falls. Never allow the soil to become soggy, to avoid causing root rot and fungal diseases.

Add 1 teaspoon of 10-10-10 nitrogen, phosphorous, potassium water-soluble fertilizer and 1 gallon of water to a watering can. Stir the solution with a spoon until the fertilizer dissolves completely. Apply the fertilizer to the ground surrounding the plants at a rate of 1/4 gallon per 2 1/2 square feet of soil. Apply the fertilizer every three to four weeks throughout the growing season.

Cut the flowers from the pentas' and lantanas' stems with a pair of pruning snips once their colors fade and their petals begin to fall. Make each cut 1/4 inch above the first or second set of leaves located below each flower.

Check the leaves on all plants for the presence of aphids, spider mites, scales or mealybugs each time you water. Spray the leaves with a steady stream of water from a garden hose to knock small populations off the foliage. Spray large insect populations with insecticidal soap or neem oil to eradicate them.