How to Grow Boxwood Basil (Ocimum basilicum)

By Matt Gibson

Want to know how to grow boxwood basil in your garden? Look no further! This article will tackle everything you need to know about this highly ornamental basil plant. Among the many varieties of basil that can be used for culinary reasons, boxwood basil is one of the most aesthetically pleasing varieties of basil, and one of the easiest to grow. 

The leaves of the boxwood basil plant are smaller, dainty, and softer to the touch than the leaves of the traditional basil plant, but they are packed with the same amazing flavor and aroma. The taste and smell of basil is inviting and complex. It is simultaneously peppery, sweet, light, and somewhat minty. The addition of basil alone can turn a bland pasta sauce or mundane soup into a savory dish to remember. 

The boxwood basil is a compact, round, bushy shrub that grows from eight to fourteen inches high and wide, making it a perfect pick for garden bed edges, large containers, or fashioned into topiaries. Boxwood basil grows very quickly in warm weather, and can be harvested until mid to late fall, but the most fragrant and flavorful harvests will come in the late spring. Be sure to harvest and freeze the excess of all of your basil just before the first frost to use during the winter to add some depth to those hearty winter stews and soups. 

Boxwood basil is a great pick for garden edges, pots, and window boxes, but be sure to keep this flavorful herb near the kitchen so that you don’t forget to put it to use early and often during the growing season.   

Varieties of Basil

Although we’re specifically covering boxwood basil now, there are many different varieties of basil that are cultivated for culinary and medicinal purposes, from the more commonly known sweet basil that is used in Italian cuisine, to the many different varieties that are used in asian cooking, from Thailand to Japan. Here’s a list of some of the more commonly grown varieties of basil: 

French Basil, Lettuce-Leaf Basil, Thai Basil, Lemon Basil, Boxwood Basil, Holy Basil, Nufar Basil, Purple Ruffle Basil, Red Basil, Dark Opal Basil, American Basil, Licorice Basil, Egyptian Basil, Magical Michael Basil, Bush Basil, Genovese Basil, Lime Basil, Superbo Basil, Siam Queen Basil, Red Rubin Basil, Sweet Dani Basil, Cinnamon Basil, Amethyst Improved Basil, Queen of Sheba Basil, Osmin Purple Basil, Greek Basil, Blue Spice Basil, Minette Basil, Fino Verde Basil, Queenette Basil, Napoletano Basil, Marseille Basil, Serata Basil, Spicy Globe Basil, Mrs. Burns’ Lemon Basil, and Pistou Basil (Imagine the intense brilliance of a pesto made from all of the different basil varieties listed here). 

There is a type of basil for just about every need imaginable. Gardeners who choose boxwood basil or bush basil, are likely looking for a highly ornamental basil plant that they can grow strictly for its lush foliage and spring flowers, or to shape it into a topiary, but would like to have the option of bringing the leaves into the kitchen for culinary application when needed. Boxwood basil is a great fit for gardeners with that specific set of needs. The plant’s dense foliage is perfect for topiary designs, and when needed, boxwood basil leaves are a great choice for making pesto. 

Growing Conditions for Boxwood Basil

Hardy to USDA zones 9-11, Boxwood basil is a tender annual that enjoys warm weather and soil like most other basil varieties. Mature boxwood basil plants need a location that has full sunlight exposure and well-draining soil. Give your boxwood basil plants about an inch of water per week, which should keep them moist but not waterlogged. If you are growing your boxwood basil plants in containers, you may need to water more often to keep moisture levels where they need to be.   

How to Plant Boxwood Basil

Start seeds indoors 3-4 weeks before the last frost in your area. Lightly cover seeds in a good soil medium and do what you can to keep the soil moist. If temperatures stay around 70 degrees fahrenheit, germination should only take about 5-10 days time and seedlings should start to sprout up. Once your seedlings have their first couple sets of leaves, move the seedlings to a location with bright light and continue growing there until the outside temperatures have warmed up enough to move your plants outside. Before making the move outdoors, check to ensure that nighttime temperatures are at least 50 degrees fahrenheit or higher, consistently. 

Care of Boxwood Basil

Boxwood basil prefers a soil that is somewhat moist but never waterlogged, or soggy with water. Around one inch of water should be added per week to achieve this moisture level, but in hot climate areas, more frequent waterings will be required. If you are growing your boxwood in containers, you will also need to keep an eye on the moisture levels and water more frequently. 

Leaves can be harvested all throughout the growing season. Simply pinch the leaves back to harvest the herb, meanwhile, doing so will help ensure additional healthy leaf production. Even when you are not harvesting your basil plant back in order to make a tasty herb butter, it’s still a good idea to pinch back the plant from time to time. Not only will this encourage new growth cycles, it will also cause new leaves to grow in the place of the ones you pruned, but it will also encourage a healthier, thicker, bushier plant. 

Harvesting Boxwood Basil

It is important to harvest boxwood basil leaves, even when you are not planning to use the harvest in the kitchen, but simply discarding the leaves that you prune. If you are just going to discard them, it is still most likely worth your time to take a few moments to enjoy their aroma before tossing them out. Harvesting, even when you aren’t planning to use the leaves right away, is important for several reasons. Doing so encourages the plant to grow new leaves and promotes a thicker, bushier plant that will be more productive in the future.

Pinching back blooms as they appear is also quite important, even if you are growing boxwood basil solely for ornamental purposes. Pinching back the foliage will keep the plant producing healthy new leaves and will help keep up the structural integrity of the plant.  Pinching back the blooms is important because if boxwood basil is allowed to bloom, the plant will halt the production of new leaves and the strong basil smell and flavor will start to fade away from the existing leaves as well, as the plant is then focusing too much of its energy on making blooms and not enough energy is left over to make the best leaves possible.

Once you’ve harvested all the basil you can handle, you may want to look into drying or freezing your basil so that you can use it year round.  

Garden Pests and Diseases of Boxwood Basil

Unfortunately, the boxwood basil plant is susceptible to a wide range of diseases and fungal infections, as well as a go-to for a handful of garden pests. Prevention of these diseases and pest infestations can be a time consuming issue to tackle, but if you already know what you might be facing down the road, you will be better prepared to deal with it when the problem presents itself. 

Boxwood basil  is sometimes a victim of Cercospora leaf spot, Downy mildew, Gray mold, and leaf spot, all of which are problems that arise due to fungal issues. One way to avoid issues with fungal infestations is to water carefully at the base of the plant to avoid soaking the leaves, or splashing the leaves with lots of excess water. This watering technique is especially important when watering plants with delicate leaves and stems that cannot stand up in the wind.  

Boxwood basil is also the known target of a handful of pests including aphids, slugs and snails, cutworms loopers, owlet moths, underwings, flea beetles, grasshoppers, japanese beetles, leafminers and nematodes. 

To handle most of the fungus problems that boxwood basil might face, take a preventative stance by spraying them with a light fungicide weekly, preferably one containing potassium bicarbonate. To deal with fusarium wilt, use disease free seeds and treat seeds with warm water prior to planting to kill off any fungus. Gray mold can only be dealt with by complete removal of affected plants.

Root rot shouldn’t affect any mature plants (as long as proper drainage needs are met), but it could keep you struggling to get a seed past the seedling stage if you are dealing with root rot issues. To avoid this problem, improve soil drainage, or amend soil with a better draining medium to improve water retention issues. 

To prevent slugs and snails from feasting on your boxwood basil, keep garden trash to a minimum, promote good air circulation and reduce humidity to create a habitat that slugs and snails dislike. Handpick slugs from your garden plants at night to decrease population. You can also lure them into death by drowning by leaving out shallow dishes filled with stale beer.  

Aphids can be handled in several ways. Use a reflective mulch to deter them, knock them off plants using a jet stream of cool water, and insecticide sprays will do the trick if other methods do not. 

Loopers, cutworms, owlet moths, and underwings need to be picked off of your plant by hand, or can be deterred by insecticides. Diatomaceous earth and neem oil can be good deterrents for flea beetles, while grasshoppers either need to be picked out by hand or consumed by local birds.

Plants that show leafminer damage should be removed from the soil after harvesting and discarded. Serious leafminer infestations may require insecticidal treatment. Plant nematode resistant varieties to avoid nematode issues. If this doesn’t work, you may need to solarize your soil to get rid of nematode populations for future growing.   

Want to Learn More About Growing Boxwood Basil?

Though boxwood basil is usually grown for culinary applications, it also has a wonderful nutritional profile and a long list of health benefits. This short film teaches you all about those benefits and lists the nutritional facts of the herb as well:

Are you a visual learner in need of some hands-on instruction on how to care for your boxwood basil plant/plants? If so, this instructional video is just what you’re looking for. This how-to video teaches you all of the basic boxwood basil care needs with an emphasis on planting and trimming this herbaceous perennial shrub:

This tutorial video shows you how to plant boxwood shrubs along your walkway. For a fast-growing, eye-pleasing plant that you can harvest and put to use in the kitchen throughout the entire growing season, planting at least one boxwood basil is a no brainer:

Pruning your boxwood basil plant is important for multiple reasons. You can decide how your boxwood is shaped by making certain cuts that affect the way the plant will grow in the future. Pruning is also the way that you harvest the flavorful leaves of the plant to use in the kitchen to add a burst of flavor to your favorite recipes. This instructional film teaches you how to prune your boxwood like a pro:

One of the best ways to prune your boxwood basil shrub, is to teach it how to form a globe-like spherical shape. YouTuber Linda Vater walks you through the process step-by-step in this tutorial:

Learn More About Boxwood Basil

https://www.burpee.com/herbs/basil/basil-boxwood-prod000450.html

https://www.gardeningknowhow.com/edible/herbs/basil/growing-boxwood-basil-plants.htm

https://homeguides.sfgate.com/can-plant-boxwood-basil-house-91572.html

Two-for-One Plant: Boxwood Basil