14 Plants That Start With I

Ice Plant (Delosperma)

An old-fashioned perennial, the ice plant grows in cabbage-like rosettes, its foliage succulent during the summer and autumn months. It’s quite a striking cultivar within the autumn flower border, with bright and flat pink flowers and glaucous leaves that grow on upright stems.

It does best in well-drained soil and in direct sunlight, and butterflies and bees will often be found buzzing around its blossom. Ice plants should be divided once every few years- this will improve flowering. 


The impatiens valleriana, sometimes known as the busy Lizzie, grows in crunchy, juicy shoots that are covered with an abundance of dentate and oval leaves. Their compact green tufts look best in the summer months, as this is when their pink blooms appear on the stalks.

They develop through the summer, into the autumn. Usually an ornamental plant, the impatiens is most often used for flower beds or shady borders, and it grows best in boxes and pots. They can often be found on terraces, balconies, or as home interior decorations.

They tend to bloom better when grown in rich soil that’s both moist and permeable, and while they thrive in partial shade, they can also grow in direct sunlight. 

Incarvillea Delavayi

Sometimes referred to as the hardy gloxinia, this plant is known for producing an abundance of bright pink flowers that are shaped like bells, with hearts the shade of gold. The flowers appear in clusters atop the branchless stems, and the plant’s foliage is feathery and dark green.

They tend to grow to roughly two feet high, and should thrive in soil that’s very well drained. When the weather’s at its hottest, the plant could do with partial shade. An ideal cut flower, you’ll often find incarvillea in raised beds, containers, or rockeries. Their planting season is spring, and they flower in the summer.

Incense Cedar (Calocedrus Decurrens)

Sometimes known as the white cedar tree, this is an evergreen whose foliage is green and glossy. Its leaves are very small and scale-like, and it’s a very aromatic plant, and has no major issues with either diseases or pests.

Incense cedar can withstand very low temperatures, can grow to 12 meters, and take between 20 and 50 years to reach maturity. This plant prefers direct sunlight to partial shade, but will tolerate both sheltered and exposed positions. Its ideal soil will be well drained.

Indian Pink (Spigelia Marilandica)

The Indian pink is a perennial grown in light shade or in a few hours of sunlight, emerging in the spring and forming patches of upright stems that can grow up to 20 inches tall. Each stem will end with red, tubular flowers which open at the tip and reveal a yellow center.

If grown well, the Indian pink can have more than 75 stalks flowering simultaneously. These flowers are very inviting to hummingbirds, as are most tubular and red flowers.

The name Indian pink refers to the plant’s medicinal qualities, though it cannot be recommended for these purposes- rather, you should seek out this plant only for its horticultural purposes. 

Indigo Bush (Amorpha Fruticosa)

This false indigo bush grows to between 6 and 10 feet, forms in dense thickets, and tends to be a loose and airy shrub. The lower surface of its leaves are velvety, and are often rounded at both ends, and have a notch at the tip.

The flowers vary from purple to dark blue, and are small in size with yellow stamens that extend beyond the petal. These flowers grow in narrow clusters, or near the end of the branchlet.

They appear between April and June, and their fruit tends to be quite small. The shrub most often grows in thickets on islands and on riverbanks, and can be weedy and invasive in the northeast. 

Inula (Elecampane)

A herbal perennial, the inula has both medicinal properties and ornamental qualities. It’s a bushy herbaceous plant that flowers in the summer, usually blooming from July to October with flowers of about five inches, that have slender yellow and orange-yellow petals.

They’re low maintenance plants, and tend to only grow to between one and one and a half feet. Their spread will have similar measurements. They grow best in perennial gardens, borders, and rockeries, but can only be grown in container gardens.

Some inula plants are native to North America, and are usually found on roadsides, or in damp pastures or unmanaged fields. There are roughly 100 species in the Inula genus. 


There are multiple varieties of iris plants, but they’re all known for their intricate blooms. The flowers tend to bloom between late winter and early spring, and their range means for a variety of color in the flower bed.

They’re a low maintenance plant once their growth is established, and your only real task will be to divide them in order to assure continuous blooms. They’re abundant multipliers, so they do need to be separated once the rhizomes start getting crowded.

Iris flowers are usually purple, white, blue, and yellow, but there are multiple hybrids that have multiple colors. The most common iris in the United States is the bearded iris. 

Irish Moss (Sagina Subulata)

A prostrate herbaceous evergreen perennial that resembles moss and is native to western and central Europe, Irish moss grows in dense mats of ground hugging foliage. Their thin stems are covered with narrow leaves, and very small flowers shaped like stars grow on the stalks sporadically.

Irish moss is often used as a substitute for lawn grass, and it grows best in full sun or partial shade, in evenly well drained and moist soil. They’re best suited to containers, rock gardens, or as a groundcover, and are highly tolerant to pests and diseases.

Irish moss is a low maintenance plant that tends to grow to a height of between one inch and two inches. Its most common companion plants include lifelong saxifrage (saxifraga paniculata) and creeping thyme (thymus serpyllum). 

Ironweed (Vernonia)

Ironweed is a small herbaceous species that’s distributed throughout the world, but there are also ironweed trees and shrubs, which are more native to tropical regions. All members of this genus have toothed, lance-shaped leaves, and they alternate along the stem.

Their flowers are disks, which have overlapping bracts below them. There are certain ironweed species that bloom in autumn and are cultivated as border plants for their flowers, which grow in purple, white, and pink clusters.

They often attract butterflies, and grow best in full sun. They make for a significant presence in gardens when they start to bloom in late summer, growing to between 4 to 6 feet at maturity. The name ‘ironweed’ comes from its ironlike qualities; its stems are tough, its growing habits tenacious, and the seeds which its flowers produce have the color of rust.

Isu Tree (Distylium Racemosum)

The ise tree is an evergreen small tree or large shrub. Part of the witch hazel family, its natural habitat is evergreen oak forests. It grows best in areas that are sheltered from strong, cold winds.

Hybrids of the tree are popular landscape plants, because they’re compact, evergreen, resistant to insects and disease, and tolerant of both drought and heat.

They’re also very low maintenance. The flowers have a five-parted, red outer structure, with purple stamens and no petals. In its native locations it’s grown for its wood, which is used to make musical instruments. The ashes of the wood are often used in porcelain glazing. 

Ivy (Hedera Helix)

Known for their ability to cling to most surfaces with their small roots that grow on the stems, ivy is very low maintenance, so can be planted in places you can’t often reach without having to worry about attending to them. They grow best in shade, and in organically rich soil.

The plants are not just attractive, but useful, too- they’re often used to block unsightly views, or as the screen on a trellis. They also make a good groundcover, specifically under trees where grass can’t grow because of the shade. 

Ixiolirion Tataricum 

Most commonly referred to as the lavender mountain lily or the Siberian lily, this plant is native to Asia, Afghanistan, and Syria. It grows in slender stems that tend to have about a dozen flowers, whose colors are varying shades of violet-blue.

The flowers start out funnel shaped, but open out to be large and shaped like stars. Its foliage is grass-like, and the plant is best grown in well-drained soil with neutral pH, and in full sunlight. It does best in hot conditions, and makes an excellent cut flower. 

Impala Lily (Adenium Multiflorum)

Also known as the kudu lily or the sabi-star, this plant is a deciduous succulent shrub. It’s best known for its fleshy trunk and its flowers of pink and white. Its flowering time tends to be from late autumn to early spring, once the leaves have all dropped. It can only grow in areas that are warm and dry, like South Africa, central Africa and East Africa. 

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