10 Plants for Gardens with Alkaline Soil

Choose the right plants for an alkaline planting site, and watch your flowers and foliage thrive.

By: Lynn Coulter

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Photo By: Bailey Nurseries, Inc.

Photo By: ProvenWinners.com

Photo By: Bailey Nurseries, Inc.

Photo By: National Garden Bureau/Longfield Gardens

Photo By: ProvenWinners.com

Photo By: iBulb.com

Photo By: Ball Horticultural Company

Photo By: ProvenWinners.com

Photo By: Bailey Nurseries, Inc.

Deutzia 'Nikko'

For beautiful, healthy plants, you may need to adjust the pH of your planting site (pH is a number between 0 and 14 that refers to how acidic or alkaline your soil is). A soil test kit, available online or from garden centers and hardware stores, measures the pH, so you’ll know whether or not your soil needs amendments.

The first step in testing is taking dry soil samples from different parts of your garden. Mark the test tubes from the kit to indicate where each sample came from (the pH may vary across your planting site, requiring different amendments in different places). Mix the soil with the chemical solution in each tube.

Deutzia 'Yuki Cherry Blossom'

Now compare the solution colors to the chart in your kit. Dark green indicates alkaline soil (a pH above 7). Bright green is neutral (a pH of 7). Yellow and orange indicate acidic soil (a pH below 7).

Deutzia gracilis can adapt to a wide range of pH levels. This deciduous shrub is happy in mildly alkaline soil, as long as it drains easily and stays moist, but not wet. Deutzias bear clusters of small flowers in spring and are attractive in winter, thanks to their peeling bark. This variety, 'Yuki Cherry Blossom' explodes with pink petals each spring.

Caryopteris

Better known as bluebeard, Caryopteris x clandonensis is a woody perennial with aromatic, gray-green leaves. From late summer into fall, it bears clusters of bluish-purple flowers. This attractive plant is adaptable enough to grow in neutral, slightly acidic or slightly alkaline soils. If your garden spot is strongly alkaline, you can "sweeten" it, or decrease the alkalinity, by adding organic matter, garden sulfur or sphagnum peat or by mulching with acidic pine needles.

Clematis

Clematis vines prefer neutral to slightly alkaline soils. Some gardeners with acidic planting sites add lime or wood ash to adjust their pH, but check the results from your soil test before you add or reapply amendments. Wood ash, for example, breaks down fast and has to be reapplied often, which can get your soil out of balance. This clematis, 'Hakuba,' has pale lavender blooms brushed with light green. The flowers, which are are magnets for butterflies, open in late spring and gradually become white.

Forsythia

Although most garden plants can tolerate a wide range of soils, they usually grow best in neutral to slightly acidic soils. Forsythias are flowering shrubs that adapt well to alkaline soils. These deer resistant beauties bloom profusely in full sun, but can take partial shade. 'Show Off' forsythia, a compact variety that doesn't need pruning, opens its bright yellow flowers in early spring.

Barberry

Barberry shrubs are a nearly carefree choice for planting in alkaline sites. Thanks to their rich foliage colors, they provide interest until frost, and they resist the hungry deer and rabbits that feast on more succulent plants. Sunjoy 'Mini Maroon' Barberry is a non-invasive variety that doesn’t produce annoying seeds, as some others do. Grow these plants in containers or in the landscape, and give them full sun to partial shade.

Crocus

Plant crocus corms, which are bulb-like storage stems, in neutral to slightly alkaline soils for early spring blooms. If the pH in your garden is too high or too low, plants can't get the nutrients they need and may weaken and die. If you add amendments to your planting site, it's a good idea to re-check the pH every year with a soil test kit.

Photinia

Red-tip photinias (Photinia fraseri) are evergreen shrubs, hardy in USDA zones 7-9. Give them full sun and they’ll thrive in alkaline soils that drain easily. If your soil is highly alkaline, and the plants develop yellow leaves with green veins, they may not be getting enough iron. Apply iron chelate, following the package directions, and keep the soil around the plants moist, but not soggy. Photinia 'Fireball Red’ has a compact growth habit, so you can use it in containers.

Lilac

Give your lilacs full sun, and they’ll reward you with fragrant spring flowers you can snip for bouquets or leave on the plants to attract beautiful butterflies. This reblooming lilac, 'Bloomerang Purple', (Syringa) likes fertile soils, good drainage, and a pH that ranges from neutral to alkaline. If your garden spot is too acidic, amend it with garden lime in the fall. Most lilacs need a long period of cold weather to set blooms, but there are newer varieties for warm winter regions.

Buddleia

Lo & Behold 'Blue Chip’ is a miniature butterfly bush (buddleia) that seldom needs more than light trimming. Like most buddleias, it can tolerate alkaline soils. If your planting site is too acidic, butterfly bushes will show their displeasure by producing yellow or undersized leaves; sometimes leaf margins may look wavy or curled. Applying ground lime will help. You might also consider planting near a driveway or other concrete structure. As rain washes lime out of the concrete, the soil around it often becomes more alkaline.

Boston Ivy

Boston ivy and its relative, Virginia creeper, prefer alkaline soils. Both vines take on brilliant, show-shopping colors in fall, especially when they’re grown in full sun. But both grow aggressively and can be difficult to remove from walls and other structures. In fact, they can actually cause damage, so be careful where you plant them. Honeysuckle and winter jasmine are other vines that will grow in a slightly alkaline garden or landscape.

10 Plants for Gardens with Alkaline Soil

Related To:

Shop This Look

Deutzia 'Nikko'

Deutzia 'Yuki Cherry Blossom'

Caryopteris

Clematis

Forsythia

Barberry

Crocus

Photinia

Lilac

Buddleia

Boston Ivy

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