Articles

Rock Gardening for Beginners

Callirhoe involucrata
Callirhoe involucrata is a charming, heat tolerant summer bloomer for the rock garden.

Rock garden plants have an elfin, seductive charm all their own. Hailing from windswept, mist-shrouded summits, rocky slopes, craggy coastlines, and other picturesque and often challenging habitats, they somehow embody the mystery and majesty of their native haunts. Make their acquaintance and you will almost certainly yield to their spell.

Clematis fremontii
Clematis fremontii is an unusual, attractive species fit for rocky garden spaces.

Just about any garden can accommodate at least a few of these beguiling rock-dwellers. Moreover, their diminutive size and their preference for rocky niches make them some of the best subjects for space-challenged gardens. Tucked into a patio wall, or nestled in a clay pot, or associating in an alpine trough, they excel at bringing character and ornament to garden nooks and crannies. They even work well in urban settings.

Growing Rock Garden Plants

Getting them to grow happily in a domesticated habitat is another matter. To simulate a boulder-strewn mountaintop can be a bit of a trick if you garden in central Manhattan. Fortunately, many popular rock garden plants are relatively undemanding, taking well to most well-drained soils (although varying in other requirements such as exposure and soil acidity). As for the fussier types, most do well in humus-rich, nutrient-poor, gritty soil that stays moist in spring and cool and relatively dry in summer. A little Fafard® Sphagnum Peat Moss makes a fine amendment for gritty soils in need of added organic matter. Of course, almost all rock garden plants do best (and look best) in the company of rocks, which buffer their roots from heat and their stems from cold and dampness.

Building a Rock Garden

If you garden in coastal or upland New England or the Rockies, your unamended back yard may make the perfect rock garden habitat. In less craggy regions, however, some modifications may be necessary. To create a large rock garden habitat on well-drained but stone-free soil, bury large flattish rocks at a slight upward angle with their tips exposed. Place the rocks in such a way that they suggest the edges of an underlying rock ledge. Surface groupings of a few rounded boulders also work well.

Sisyrinchium idahoense flower
Sisyrinchium idahoense offers delicate starry flowers over grassy foliage.

Build small rock gardens from scratch by burying rocks in mounded growing medium, or by sandwiching the growing medium between stone retaining walls. A mixture of equal parts topsoil, coarse sand or grit (such as calcined clay), and Fafard compost makes an excellent medium for many rock garden subjects. The same mix can be used to create growing pockets in existing stone walls. For a micro-garden that can reside on your patio or at your doorstep, buy or make an alpine trough – a tub-shaped planter specially designed for alpine plants (see how to build and plant one at this link).

Easy Rock Garden Plants

Among the seven best plants for beginning rock gardeners (or any rock gardeners, for that matter) are:
1. Fan columbine (Aquilegia flabellata) and other dwarf members of the genus Aquilegia. Hummingbirds adore them.
2. Campanulas, including Carpathian harebell (Camanula carpatica) and Dalmatian bellfower (C. portenschlagiana). Both do well in full to partial sun and any not-too-soggy soil.

Dianthus gratianapolitanus 'Grandiflorus'
Dianthus gratianapolitanus ‘Grandiflorus’ is an easy charmer for early summer rock gardens. (image by Jessie Keith)

3. Cheddar pink (Dianthus gratianopolitanus), alpine pink (D. alpinus), and others of the Dianthus tribe, featuring grassy leaves and fringed, spicy-scented flowers. Most prefer full sun and alkaline soil.
4. Beardtongues such as hairy beardtongue (Penstemon hirsutus) and pine-leaf beardtongue (P. pinifolius). Hummingbird favorites, they thrive in sun, acid soil, and low humidity.
5. Lewisia cotyledon and its many beautiful selections and hybrids. This native of Northwest mountains loves cool, gritty, lime-free soil, and an east- or north-facing slope.
6. Phlox stolonifera, P. divaricata, and other low-growing phlox. The two mentioned here are best in partial shade.
7. One of the most beautiful Eastern woodland natives, bloodroot (Sanguinaria canadensis), which occurs in nature in shady, rocky habitats. Double-flowered forms (such as ‘Multiplex) are especially beautiful, and relatively long-blooming.

Sanguinaria canadensis 'Multiplex'
Sanguinaria canadensis ‘Multiplex’ is a double-flowered ephemeral ideal for spring rockeries.

Zinnias for Colorful Containers & Cut Flowers

Pink and apricot profusion zinnias
Pink and apricot profusion zinnias add soft color to this midsummer flower garden.

Zinnias are summer workhorses in the flower garden. They keep producing radiant flowers—even in the worst heat—and come in a wide range of sizes and colors making them adaptable to practically any garden space. Their value as premium cut flowers and favorite bee and butterfly plants makes them that much more appealing to gardeners. No summer garden should be without a few zinnias.

Tall cactus flowered zinnias
Tall cactus flowered zinnias are some of the nicest zinnias for bouquets.

Tall Zinnias

The long stems, large flowers and bushy stature of tall zinnias (Zinnia elegans) have led to their wide popularity. These easy-to-grow Mexican natives will bloom from summer to frost, if they are deadheaded and moderately maintained. Their flowers have single, semi-double, or double petal arrangements and come in many forms including cactus, dahlia, button, button-like pompons and ruffled forms. What’s more, there are tons of colors available. The pallet includes red, pink, white, green, orange, salmon, yellow and lavender. There are also many bicolored and tricolored varieties. One of the best color combos – for garden or case – is a vibrant mix of pink, rose, green and apricot colored flowers.

Dwarf Zinnias

Zinnia plants vary in height from 1-4 feet, depending on the cultivar. Shorter “tall zinnia” varieties, such as the many large-flowered, short-statured varieties in the Magellan Series, are perfect for containers and low flower borders while wild, free, long-stemmed forms look great in tall borders, vegetable gardens and cutting gardens. The ever-popular chartreuse green ‘Envy‘, rose and green ‘Queen Red Lime‘ and ruffled salmon apricot Senora™ are three complimentary long-stemmed, double-flowered varieties ideal for making quick, vibrant flower arrangements.

Double Zahara Fire
The vibrant Double Zahara Fire is one of the best zinnias for containers and borders.

Bedding Zinnias

Hybrid bedding zinnias are the best for container gardening. These include the wonderfully versatile and lovely single-flowered Profusion zinnias, which come in all colors, and award-winning double-flowered Zahara™ zinnias. The bushy, spreading, slightly taller (18″-24″) ‘Uptown Grape‘ is also a new variety lauded for its prolific blooms and exemplary disease resistance. Another wonderful compact species is the Mexican native Zinnia angustifolia—with ‘Star Orange‘ and the hybrid Raspberry Lemonade Mix being top sellers.

Growing Zinnias

Getting started with zinnia growing is simple. Each spring, in late April to early May, choose the best sunny spot for your zinnias. Clean out the weeds and debris from the area, then work up and smooth the soil. Amend the beds with Fafard Premium Natural & Organic Compost Blend until the soil is light and friable. Finally, surface-sow the zinnia seed, lightly pat them in and gently water. Then keep the planted area evenly moist. Within a week or so your seeds will start sprouting up. From there, it’s just a matter of keeping the plants reasonably hydrated and thinned to a foot apart. Purchased, container-grown zinnias thrive in large pots filled with moisture rich potting soils, such as Fafard® Natural & Organic Potting Mix. Growing zinnias is that easy!

Fafard Premium Natural & Organic Compost Blend pack
Amend zinnia beds with a fertile amendment like Fafard Natural & Organic Compost Blend.

Cutting Zinnias

Zinnia flowers are most spectacular in mid to late summer, so this is the best time to make beautiful table bouquets with long-stemmed varieties. To make a simple zinnia arrangement, choose newly opened, fresh stems and cut them to around 8-12 inches in length. Remove the leaves from the lower part of the stems and then gather the flowers into a tidy, mounded bunch; trim the bottoms uniformly and place them in a vase filled with about 2 cups of water spiked with 1 tablespoon of sugared lemon soda (a great cut flower food). That’s all there is to it!

Zinnia Pests, Diseases, and Problems

Zinnias can have a few troubles. Really tall cultivars can flop in the wind and may need to be staked. The leaves may also develop powdery mildew and leaf spot while also attracting hungry Japanese beetles. To keep my zinnias mildew-free, I gently hand-wash their leaves and space plants well to encourage good air flow. This also discourages outbreaks of fungal spotting. The all-natural GreenCure is also a wonderful remedy for powdery mildew. Another option is to plant disease-resistant selections like the Dreamland Series. To control Japanese beetles, simply pick them off and drown or squash them.
Follow these simple guidelines and you’ll have spectacular zinnias until frost. Whether enjoyed from a patio or balcony or cut and brought indoors to dress up a table, zinnias will bring rich, easy color to your summer life.

Zinnia angustifolia 'Star Orange' flowers
Zinnia angustifolia ‘Star Orange’ Flowers growing in a large container.
Pretty button zinnias
Pretty button zinnias (left) add bright color to this cutting border.

Heat Tolerant Greens for Summer

Swiss chard
Swiss chard is a delicious, heat-tolerant green that’s as pretty as it is tasty. (photo by Jessie Keith)

When temperatures heat up in early summer, the tender lettuces of spring bolt, choosing to obey the biological imperative and produce flowers and seeds instead of toothsome leaves. Gardeners understand the process, but those of us who are salad lovers still crave home-grown greens to complement bold summer veggies like tomatoes and peppers. Fortunately, salad salvation is easy to find in the form of heat-tolerant greens for summer.

Fafard Ultra Outdoor Planting Mix pack
Fafard Ultra Outdoor Planting Mix is recommended for growing greens.

These leafy garden favorites range from low-growing plants perfect for container culture to statuesque specimens that can serve as anchor plants in ornamental potagers or edible landscapes. Seeds or starter plants for these summer-loving salad species are easy to obtain from garden centers or online vendors. Plant them in high-quality planting media, like Fafard Premium Topsoil or Fafard Ultra Outdoor Planting Mix, and you can raise a steady supply of cool greens in even the hottest weather.

Malabar spinach
Malabar spinach is both an attractive vine and edible green.

Swiss Chard

Swiss Chard (Beta vulgaris var. cicla): Possibly the most glamorous member of the beet family, spinach-like Swiss chard has been fashionable for the last decade or so because it is as beautiful as it is delicious. Varieties like ‘Orange Chiffon’ or ‘Bright Lights’ dominate the vegetable garden with leaves, stems, veins or ribs that shine in shades of green, red, orange, pink, bronze, purple or silver. Chard is versatile and can be grown in-ground or in large containers. In the heat of summer, harvest the young leaves regularly for salads. Later on, reap mature leaves and stems for cooked dishes.

Malabar Spinach

Malabar Spinach (Basella rubra): Gardeners who crave greens and live with space limitations can harvest tasty leaves all summer by growing Malabar spinach, a twining, climbing plant, native to Africa. Though unrelated to true spinach, the mild-tasting, crinkled leaves thrive in hot weather and can be harvested young for salads. Striking reddish stems and older leaves lend a spinach or chard-like flavor to cooked dishes. Malabar spinach is a perennial, but can be grown as an annual in cold winter climates. Planted in-ground or in containers, the vines should be trained on trellises or pillars for best results.

New Zealand Spinach

New Zealand Spinach (Tetragonia tetragonioides): Another good spinach or chard-like green is New Zealand spinach, also a vining plant that can reach up to 2 feet tall when tied to a support. Featuring thick, pointed, green leaves, New Zealand spinach thrives best in a consistently moist environment. Harvest leaves regularly throughout the summer to promote continued production of fresh, tasty foliage. The plants tend to be prolific self seeders, but removal of flower stalks will control this problem.

Tart purslane leaves
These tart purslane leaves have been washed and spun and are ready to eat!

Garden Purslane

Purslane (Portulaca oleracea var. sativa): Step on a crack in midsummer and you may find yourself right on top of one of the most nutritious and heat-tolerant summer greens. Known as “verdolaga” in Spanish, common purslane is a low-growing, plant with mild, lemon-flavored leaves. Cultivated varieties, like ‘Gruner Red’ and ‘Goldberg’ golden purslane, are larger than the wild types, with a somewhat upright habit. The species relatively diminutive nature makes it easy to grow in pots. Pinch back growing tips to stimulate bushy leaf growth and prevent the flower formation that leads to weedy proliferation. Harvest leaves regularly.

Vegetable Amaranth

Vegetable Amaranth (Amaranthus tricolor and other species): Related to the much-loved garden annual, love-lies-bleeding, vegetable amaranth is well known as an heirloom seed or grain producing plant. In many cultures cooks have long harvested the nutritious, edible leaves throughout the growing season for salads, as well as traditional soups and stews. Extremely heat tolerant, amaranth plants quickly grow 2 to 5 feet tall, depending on species and variety, thriving in warm weather with relatively little supplemental water. Amaranth leaves are often decorative enough to hold their own in a mixed-use, ornamental/edible planting scheme and may be marked with green, red, or a combination of the two colors. Terminal shoots should be pinched to promote branching.

Orach

Sea Purslane, Mountain Spinach, Orach (Atriplex hortensis): Annual orach is a slightly spicy green that will also add a colorful kick to edible landscapes. The tall stalks top out at 5 to 6 feet tall in summer, bearing pointed leaves that may be green, shades of pink and red, gold or purple. Eaten fresh or cooked, orach leaves grow on plants that are both heat and cold tolerant. Golden-leafed varieties are prized in Europe for fine flavor.

Standard salad greens
Standard salad greens are cool-season plants that won’t stand up to summer heat. (photo by Jessie Keith)