The potted herb garden is easy


American Botanical Garden horticulturalist Adam Pyle explains the benefits of potted herbs and shows how to potty dry and wet herb gardens. (Adrian Higgins and Sandi Moynihan / The Washington Post)

Beautiful, delicious, aromatic and self-sufficient, herbs represent a form of perfection in the garden.

Culinary herbs are especially suited to growing in pots and other containers – they like dry, airy perches. People love them too: you can place a potted herb garden almost anywhere with a little sunshine, on a covered walkway, balcony, front porch, or back patio. The only criterion, apart from sunlight, is that it is practical, so that you can prune what you need for the kitchen. Herbs love to be pruned; they react by becoming more bushy.

May is the month to assemble your herbs. The weather is warm enough, finally, to appeal to heat seekers, like basil and lemongrass, and to bring mint to life for Kentucky Derby juleps.

And if I haven’t fully explained how easy, inexpensive, and foolproof it is to grow herbs in pots, and how much I want you to do, let me just say: GROW HERBS IN POTS.

Here’s how to do it:

Containers

The bigger the container, the better. A larger volume of soil moderates the temperature of the roots, retains moisture, and leaves room for the growth of overcrowded grasses. A 14 inch diameter pot is ideal for holding four to six herbs, don’t go with something smaller. Shapes, colors and materials vary widely.

If you’re on a budget, a simple basic plastic or clay pot costing a few dollars will do. If you have deeper pockets and want to make more of a design statement, you can find glazed ceramic pots for around $ 30 to $ 60, smart terra cotta pots for $ 40 to $ 100, and high-design concrete or resin pots for up to $ 200 or Suite. Metal containers can look fancy, but they get uncomfortably hot in the summer in Washington, as do black or dark pottery.

All pots should drain freely, so make sure they have at least one drainage hole. Decorative “feet” – three per pot – are inexpensive and can make a vital difference in preventing waterlogged roots, especially if the pot sits directly on concrete or stone pavers.

A grouping of pots can provide a focal point and expand your range of herbs, but avoid a lot of small pots. Three beefy pots of different diameters and heights can look great, define a corner of a patio, or visually light up corners and walls.

Ground

No potted plant will thrive in poor, dense soil. Do not use garden soil or leftover pots from last year. Classic general purpose potting soil is a peat-based mixture with perlite and limestone, often with compost and vermiculite added. You can make your own or buy ready-made bags. For herbs, especially Mediterranean herbs such as rosemary and lavender, some gardeners like to add gravel or chicken gravel to the mixture to aid in drainage. Adding sand may not help much.

Planting combinations

In creating any effective container garden, the pros give plants three distinct roles: as a right accent, as a lower growing mound, and as a creeper. They are known in the trade as “thrillers, fillers and weirs”. The same principle applies to potted herb gardens.

We asked United States Botanical Garden horticulturist Adam Pyle for some of his favorite herb combinations:

Decorative mediterranean

In an elegant square-topped terracotta planter, he placed four plants: an upright rosemary, a rue, a silver leaf curry plant (Helichrysum italicum) and a variety of oregano called Kent Beauty.

Floral twist

In a blue enamel jar, Pyle assembled a lot of curly parsley, which collapsed and served as both a filling and a spill. For height, he used feathery bronze fennel alongside a form of variegated and small-leaved basil named Pesto Perpetuo. To give visual oomph, he added two annuals with edible flowers: nasturtium (whose peppery leaves also spice up a salad) and a common marigold. Another group of marigolds, called Signet marigolds, have finer leaves and flowers and are well suited for the herb container.

Standard herb combo

In a green ceramic pot, Pyle selected five herbs that tolerate humidity (with adequate drainage). As a thriller, he put in a small pepper plant. Hers was unnamed, but I suggest a diminutive and fruitful sweet pepper named Beautiful golden baby. He added dill (Bouquet variety), which is a cool season herb. Once it has weakened in the heat of early summer, you can replace it with a fragrant geranium. He added a variety of red leaf basil and a nasturtium from a group called Alaska, which are more heat tolerant than other nasturtiums. He ended the set with a common oregano named Hot and Spicy.

Mediterranean cuisine

Pyle likes to put dry Mediterranean herbs in clay pots, which are porous and wick moisture from the soil faster than other types of containers. It also adds extra drainage by placing gravel or other small stones at the base of the pot, incorporating chicken gravel into the soil, and covering it with a mulch of small pebbles. You can use washed gravel. Pyle uses an expanded glass product named Growth stone.

In this recipe, he used rue (used little as a culinary herb, but with a nice fine blue-green texture), a new variety of chives named Cha-Cha, silver santolina, Hidcote English lavender, compact with indigo blossoms, and a caraway-scented thyme, renowned for its caraway flavor, fine texture and resistance to rot.

Perennial herb combo

Here is my recipe for herbs that are winter hardy and will give many years of service. It should be noted that most herbs are short lived plants, especially in pots, and should be replaced after about three years. Plant them in a frost-resistant container (not standard terracotta) and don’t forget to move the pot to a sheltered location in winter. This will protect the pot from frost damage and nourish the herbs. (A pot is a cooler environment than a garden bed.)

I have suggested five herbs: The trick is to use rosemary as a diffuser by selecting a end type like Prostratus. For the thriller, use a lavender – English or French lavender type – and fill with sweet marjoram and lemon thyme, the latter being a yellow variegated thyme with citrus oils. Finish the medley with a bunch of chives.

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Terri S. Tomasini