Welcome to Ask a Flower, the Q/A blog series that answers the questions you want to know!
All questions are researched and answered by the St. Andrews Garden Team. Not all questions asked may appear on this blog.
Q: What herbs do you grow at the library?
A: Richland Library St. Andrews currently grows oregano, sage, thyme, and lemon balm. If you’d like some fresh herbs, come find us in the garden most mornings, or ask staff at the desk. We harvest whatever veggies are ready on Tuesdays by 11am, and we can snip some herbs anytime garden staff are available.
Q: What are good herbs to grow in SC?
A: Many common garden herbs are from the Mediterranean or India. Mediterranean herbs are suited for hot and dry climates, so these do well as full-sun container herbs in South Carolina, but not as well in poor-draining clay. These include oregano, thyme, sage, and rosemary. Indian herbs, including basil and mint family members such as lemon balm, need more moisture and less unrelenting afternoon sun. It’s generally a better idea to grow mints in a container, as they are energetic spreaders. Many annuals (including basil) need more water than their perennial cousins. For more information on a range of herbs growable in SC, see https://hgic.clemson.edu/factsheet/herbs/ .
Q: What herbs are good to grow inside?
A: You can grow most herbs indoors, but the most important thing to realize is that they need sun. Many of the most recognizable herbs originated in the Mediterranean—like rosemary and oregano—so they naturally need a lot of light. Most sources seem to recommend 6 hrs of light a day, although some herbs like parsley and thyme can do with a little less. It’s also important to watch how warm they are in the window. In the summer, the windowsill will be warmer than the rest of the house, and in winter, the windowsill will be cooler. Herbs like basil enjoy warm temperatures of at least 70° and don’t do well in temperatures below that.
Q: How do I keep my herbs from bolting?
A: Keep plants in a cooler or slightly shadier location. This should keep the temperature lower for a bit longer and slow the plant's development.
Put plants out in the garden a little earlier in spring so you can extend the cool growing season for them. The plants will still bolt when the weather gets hot, but you'll have more time in cooler weather for abundant leaf growth.
Pinch back flowers further down the stem than you probably have been doing--about 1-1/2 to 2 inches. Pinching back at the base of the flower usually works, but going further down the stem can sometimes buy you more time before the flowering process starts all over again.
Start harvesting leaves while the plant is still immature. The more leaves you harvest, the more energy the plant will expend on leafing out rather than on flower production. This really well works for a while, but nothing works forever. Take only a quarter to a third of the stem at a time.
Harvest the plant throughout the growing season. Do this three or four times from spring to fall (or whatever your season happens to be).
Q: Is it bad that the oregano [at St. Andrews] is flowering?
A: It is true that for herbalism purposes, one generally pinches the flowers of herbs like basil and oregano to encourage the plant to focus on leaf production rather than seeds. The best time to harvest oregano leaves is just before the plant flowers. However, the flowers are also edible, and most importantly, bee magnets. Our library’s blooming oregano has been attracting all sorts of pollinators, and even predatory insects such as the syrphidae flies that hunt aphids. These insects lured into the garden by our pollinator flowers then turn around and pollinate or hunt among our less attractive vegetable flowers. Every morning I usually witness around 15 - 30 creatures buzzing in the oregano patch. It’s the busiest corner of the garden!
Q: My basil's leaves are really pale, but they get full sun. What's going on?
A: There are a number of reasons for a basil plant turning pale (even with plenty of sun), and determining the reason isn’t always easy.
Improper watering – Root rot, a result of too much water, is one of the most common reasons for yellow leaves on basil plants. Water basil only when the top 1 to 2 inches of soil is dry, and remember that slightly dry soil is healthier than soggy soil. As a general rule, one deep watering every 7 to 10 days is adequate. If you grow basil in a container, be sure the pot has at least one drainage hole. Basil is a thirsty plant. It needs watering during the summer more often than once a week. The wilting leaves will let you know!
Fungal disease – Although several fungal diseases can cause yellow leaves on basil plants, downy mildew is one of the most common. Downy mildew is a fast-spreading fungus recognized by yellowish basil leaves and a fuzzy, gray or brown growth. If you catch the problem early, you may be able to stop the spread by clipping affected growth. However, badly affected plants should be removed and disposed of carefully.
Aphids – Aphids are tiny pests that suck the juice from tender foliage, thus causing yellow leaves on basil plants. Look for aphids on the undersides of leaves and on the joints of stems and leaves. Aphids are easy to control with insecticidal soap, but be careful not to apply the soap when the sun is directly on the leaves or on hot days, as the soap can scorch the plant.
Root knot nematodes – These small, soil-dwelling pests can cause yellowish basil leaves and small galls on the roots. The best recourse is to harvest the plant and use the healthy leaves. Next time, plant resistant varieties in soil not affected by nematodes.
Lack of nutrients – Basil is a hardy plant that does well in poor soil, but it still requires nutrients in order to thrive. Fertilize basil regularly to prevent yellowish basil leaves, using an all-purpose balanced fertilizer.
Q: Do herbs require regular pruning?
A: Technically, no. Your herb plants will not spontaneously combust if they are not pruned. However, pruning is the best way to encourage new, healthy growth, and can help you control the size of your garden.
The first thing you must know is what kind of herb you’re dealing with: herbaceous or evergreen. Herbaceous herbs are generally the ones with bigger leaves and include oregano, chives, and mint. These herbs will wilt during the winter. Because of this, less care is needed for how much is pruned off—as long as you leave at least 1/3 of the plant left. Whenever these plants start to bolt or simply need harvesting, that’s a good time to prune. Use scissors and cut the leaves right where they meet the stem. You might also be able to use your fingers but don’t tear or rip off pieces of the plant’s stem. Like a scrape for humans, this can leave the plant vulnerable to diseases.
Some herbaceous herbs require a little more TLC. For example, it is important to trim basil plants back as they mature. This will also allow the plants to get bushier because multiple stems will appear from a single stem. This is called “tipping.” It is best to start this process when they are only a few inches tall. Always start from the top—something true for ALL herbaceous herbs when pruning/harvesting.
Evergreen varieties require different care. These herbs can be more “twiggy” and include thyme and rosemary. They are made to withstand winter’s chill by hardening their supple stems into more twiggy structures as they mature. They need to be trimmed so they don’t become too woody too fast because it prevents new leaf growth. As new growth happens, you can harvest to encourage more growth. To prepare for winter, prune back evergreens to the woody stems.
Q: My basil isn't getting bushy. They look more like stalks. How do I fix that?
A: To make your basil bushier, consider how you are harvesting your basil leaves.
When harvesting, you should cut off the stems instead of picking leaves directly from the plant. Stems should be cut strategically in order to prune the plant, with future growth developing bushiness.
To prune basil, first look for two sets of small leaves on either side of a stem. In the left-hand photo below, the red arrows point to an example of the two sets of leaves. Once those leaves are located, cut the middle stem, on an angle, about a half inch above where the leaves meet. The red slanted line in the photo indicates where to cut.
The right-hand photo shows what the basil plant looks like post-trimming. This photo is from another angle. The trimmed stem is in the middle of the red circle. The two sets of leaves are visible on either side of the trimmed stem.
Now, harvest your basil leaves from your cuttings, and continue to prune your basil plant until you have enough leaves harvested or you run out of places to trim stems.
Q: Help! I'm not eating my herbs fast enough. Is it hard to dry them?
A: No worries about not eating them fast enough! Herbs can grow more than you can use in one season. Air drying your herbs is the quickest and least expensive way to dry fresh herbs. The best herbs to use for air drying are dill, thyme, rosemary, and oregano. Freezing herbs with higher moisture content like sage, basil, chives, or mint should be done in the freezer overnight with herbs in a zip lock bag.
Air drying herbs: Cut selected number of branches from your herb bush, shake them to allow any hitchhiking bugs to fall off, pick the yellow dull looking leaves off and also any leaves about an inch or so away from the bottom of the stem, and then rinse them with cool water. Once you have rinsed your herbs, bundle them in small groups with a rubber band or string and put them into a paper bag that you have cut/poked holes into. Once you have your herbs in, take the bag and hang it upside down in a warm and airy room. To learn more, see us in September!
Freeze drying herbs:Take the whole leaves and rinse and dry them on paper towels until completely dry. Then take the individual leaves and either place them in an ice cube tray (with oil, butter, or water) and let freeze. Or you can dry the leaves individually and place them flat on a cookie sheet (not overlapping) to freeze. Once they are completely frozen, you can place them in a zip lock bag together. If the leaves are already frozen before you place them together, they will not stick.
Meet the Flowers!
The St. Andrews Garden Team is led by Marigold, our resident expert on all things plant. A life-long environmentalist at heart, she completed her certification in Native Plant Studies through the South Carolina Botanical Garden hosted at Clemson University and the South Carolina Native Plant Society on April 25, 2019, and has been growing her own fresh food since she was 22. She established the St. Andrews Garden in a distant corner on the property with Rod in 2014. It is now a front-and-center showpiece with the recent library remodel. Jessica and Lindsey T. were added to the garden team in Feb. 2018 and have apprenticed with Marigold since then. Lindsay W. joined their ranks in Aug. 2018 along with Steve in Apr. 2019.
Richland Library St. Andrews harvests every Tuesday morning. Come by for fresh veggies or to ask us some questions that can appear on our website in a future blog post! Or, email your questions to email@example.com.