Lavender, roses, and rosemary thrive in well-draining soil.

Before planting, test the soil pH to ensure it falls within the preferred range for these plants (lavender: 6.5-7.5, roses: 6.0-6.5, rosemary: 6.0-7.0).

Amend heavy clay soil with organic matter such as compost or aged manure to improve drainage.

Sandy soil can be amended with organic matter to increase water retention.Reading these two books about planting roses and lavender as companion plants will provide a wealth of information. Here are key things you'll learn.

Benefits of Companion Planting:

Understand the advantages of planting roses and lavender together, such as pest control, improved growth, and enhanced aesthetics.
Soil Requirements:

Learn about the specific soil types, pH levels, and drainage conditions that best support both roses and lavender.
Sunlight and Water Needs:

Discover the optimal sunlight exposure and watering schedules for each plant to ensure they thrive together.

Pruning and Maintenance:

Learn effective pruning techniques for both roses and lavender, as well as general maintenance tips to keep the plants healthy and vigorous.
Pest and Disease Management:

Identify common pests and diseases that affect roses and lavender, and find out how companion planting can reduce these issues naturally.
Seasonal Care:

Understand the seasonal care requirements for both plants, including winter protection for roses and strategies to prevent lavender from becoming woody.
Propagation Methods:

Learn how to propagate roses and lavender through cuttings, seeds, and other methods to expand your garden.
Design Ideas:

Explore various garden design ideas that incorporate roses and lavender, creating visually appealing and fragrant landscapes.