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What Herbs Should Not Be Planted Together

One thing to consider when growing herbs is which herbs should not be planted together. Some herbs can have a negative effect on the flavor or growth of other herbs when they are planted together or have incompatible growing needs.

Herbs growing together in a wooden planter.

Companion planting is the practice of growing different plant species together in close proximity, with the goal of improving the health and productivity of the plants.

This is achieved by taking advantage of the unique characteristics of each plant to benefit the others.

For example, some plants produce chemicals that repel pests, while others attract beneficial insects. Some plants fix nitrogen in the soil, which can be used by other plants, and others shade sensitive plants, protecting them from the harsh sun.

>> Related post: What Herbs Can Be Planted Together?

Conversely, certain herb combinations can have negative effects on each other’s growth and health.

For example, some herbs produce chemicals that inhibit the growth of nearby plants, compete for the same nutrients in the soil, or cause one or both herbs to lose their flavor.

Some herbs can also attract pests that are harmful to other plants, or even spread disease.

By avoiding certain herb combinations when planning your herb garden, you can optimize the growth and health of your herbs, and ensure that all your plants thrive.

Which herbs should not be planted together? 

Anise and coriander

Anise is a strongly scented herb that can improve the growth and health of other plants, but it can also have a negative impact on coriander.

The strong scent of anise can interfere with the delicate flavor of coriander, making it taste less desirable in cooking.

In addition, anise and coriander have different growing requirements, and planting them too close together can result in competition for water and nutrients in the soil. This can result in reduced growth and yields of both plants.

To avoid these issues, it’s best to separate anise and coriander in the herb garden. Anise can be paired with other strongly scented herbs, such as fennel and dill, which can also improve the health and productivity of the herb garden.

Coriander, on the other hand, can be paired with parsley and cilantro, which have similar growing requirements and complement the flavor of coriander in cooking.

Basil and rue

Another herb combination to avoid is basil and rue. While basil is a popular herb that’s widely used in cooking, be careful not to plant it too close to rue.

Rue is a strongly scented herb that can repel pests, but it can also have a negative impact on the growth and flavor of basil. The volatile oils produced by rue can affect the flavor of basil, making it taste bitter and less palatable.

In addition, the strong scent of rue can also deter the pollinators that are essential for basil growth and reproduction. This can result in reduced yields and stunted growth of basil.

To avoid these issues, it’s best to separate basil and rue in the herb garden. Basil can be paired with thyme, oregano, and marjoram, which have similar growing requirements and complement the flavor of basil in cooking.

Rue, on the other hand, can be paired with rosemary, sage, and lavender, which also have strong scents and are known to repel pests.

Dill and Umbelliferae sp.

Dill is a member of the Umbelliferae plant family, which also includes fennel, caraway, angelica, anise, cumin, carrots, and coriander.

When companion planting, it’s important to be aware that members of the Umbelliferae family can cross-pollinate with each other, resulting in hybrids that may have undesirable traits.

For example, planting dill near fennel or anise can result in the transfer of their strong flavors to the dill, making it taste less desirable in cooking. Cross-pollination can also result in the loss of the unique characteristics of each plant, such as flavor, growth habit, and productivity.

To avoid these issues, it’s best to separate these plants in the herb garden. This will ensure that each plant retains its unique characteristics and flavor, and that there is no cross-pollination between species.

Different varieties of mint

Sometimes, herbs neutralize each other when planted next to each other. They don’t really affect the plant’s growth and health, but they can affect its taste.

For example, planting several types of mint together can cause all three mint plants to start smelling and tasting like each other, even if they were of different varieties when initially planted.

Never plant different types of mint together because they end up combining forces and having the same smell and flavor. So plant your chocolate mint, spearmint, and peppermint far from each other to avoid pretty much having the same kind of mint.

Mint tends to grow like a weed and can easily take over a garden bed if not kept in check regularly. For this reason, I recommend growing mint in a pot (on its own). It is much easier to take care of that way!

Sage and cucumbers

Sage is a strong-scented herb that can deter pests and improve the health of other plants. However, it can also inhibit the growth of cucumbers. Cucumbers are particularly sensitive to the compounds produced by sage, and planting them near sage can result in reduced yields and stunted growth.

It’s best to avoid planting sage and cucumbers together and instead, choose companion plants that will complement the growth and health of both. For example, cucumbers can be planted near beans or nasturtiums, which are known to attract beneficial insects and improve soil health. Sage, on the other hand, can be paired with rosemary or thyme, which have similar growing requirements and can improve the flavor of sage-based dishes.

Fennel and almost anything

Fennel is a versatile herb that’s widely used in cooking. However, when companion planting, it’s important to be aware that fennel can have a negative impact on other plants in the herb garden.

Fennel produces allelopathic chemicals that can suppress the growth of other plants, and it can also have a negative impact on the flavor of neighboring herbs.

For example, planting fennel near dill or coriander can result in the transfer of its strong anise-like flavor to these herbs, making them taste less desirable in cooking.

In addition, fennel is a tall plant that can grow up to six feet tall, and it can shade out smaller herbs, reducing their growth and productivity.

To avoid these issues, it’s best to plant fennel in a location that’s separate from other herbs in the garden, or to grow it in a container where its growth can be controlled.

Different growing needs

Companion planting is a useful tool for maximizing the health, productivity, and flavor of herbs in the garden. However, it’s important to consider the different growing needs of each herb when selecting companion plants.

Plants have different requirements for light, water, and nutrients, and it’s important to choose companion plants that complement each other’s needs, rather than competing for resources.

For example, some herbs require full sun while others prefer partial shade, and some are drought-tolerant while others need consistent moisture.

When planning your herb garden, be sure to research the individual needs of each herb to ensure they are planted in the right conditions for them to thrive.

Sunlight Requirements

Herbs have varying sunlight requirements, with some preferring full sun and others preferring partial shade.

For example, basil needs full sun while cilantro prefers partial shade. Planting these two herbs together would result in one not getting the sunlight it needs to thrive.

Full-sun herbs, such as rosemary, basil, and thyme, require at least six hours of direct sunlight per day to thrive.

Partial shade herbs, such as mint, chives, and parsley, prefer dappled sunlight or protection from intense afternoon sun.

Soil Type

It’s important to match the soil type of each herb when companion planting. For example, planting a well-drained soil herb in heavy clay soil can result in poor growth and reduced productivity.

For example, sage and thyme will be unlikely to thrive if planted in the same soil. Sage needs well-drained soil while thyme prefers moist soil. If these two herbs are planted together, one will likely suffer from too much or too little water.

Water Needs

Water needs are another important factor to consider when companion planting. Planting a drought-tolerant herb next to a water-loving herb can result in overwatering or underwatering for one of the herbs.

Some herbs, such as lavender and thyme, are drought-tolerant and require minimal watering, while others, such as basil and cilantro, require consistent moisture. If planted together, it is unlikely that both herbs would thrive.

Growth Habit

Growth habit is another factor to consider when companion planting. Some herbs, such as dill and fennel, are tall and can grow up to six feet tall, while others, such as chives and parsley, are shorter and more compact.

Planting a tall herb next to a short herb can result in shading and reduced growth for the short herb.