Garden Plants: Flowering

Flower in the garden
Flower in the garden

The most popular flowering garden plants world wide include roses, lilies, tulips, irises, and daffodils. These plants range in form from herbs to bushes to trees. Their leaves, flowers, and optimum growth needs differ greatly.

Flowering plants (angiosperms) are grown in gardens for their beauty and their fragrant aromas. They and their relatives can also be grown for food. Myriad flowering plant types are grown in the world’s gardens.

Most popular flowering garden plants are in the rose family (Rosaceae, about three thousand species) and the lily family (Liliaceae, about forty-five hundred species), which together make up awide variety of herbs, bushes, and trees.

Also quite popular are members of the iris family, Iridaceae, which includes crocuses. Lilies and irises belong to the order Liliales (about eight thousand species) of herbaceous flowering plants. Other well-known plants of this order are tulips, daffodils, and hyacinths.

Roses and Lilies

The most popular garden plants are roses and lilies. Rose is the common name for members of the family Rosaceae, a family of one hundred genera and three thousand species. Included are important fruit and ornamental species, including the familiar genus Rosa (true roses).

Rosaceae and more than twenty other families belong to the order Rosales. Rosaceae grow as trees, shrubs, or perennial herbs. Within this family, food is produced by apple, pear, peach, plum, cherry, apricot, almond, and nectarine trees. Many berries, including raspberries, black-berries, and strawberries, are Rosaceae.


Since antiquity, the true rose has been among the most popular garden flowers in the world. Roses evolved from sweetbriers (wild roses). This genus of perennials, with about one hundred species, is mostly native to the north temperate zone.

Experts recognize two main classes of the approximately thirteen thousand cultivated rose varieties (cultivars) which have arisen from hybridization of a few original species, mostly from Asia. Members of the original class, such as brier, damask, and moss roses, bloom once a year, in early summer.

The others, called perpetual roses, bloom more than once a season. They include the tea roses, polyanthas, and rugosas. Tea roses smell like tea or fruit. Other roses have the distinctive rose smell or no smell at all. True rose flowers are white or various shades of yellow, orange, pink, or red.

A perpetual rose bush can grow up to 6 feet (2 meters) tall. Polyantha bushes are lowand bear flower clusters; shrub roses growup to 15 feet (4.5meters) tall. The leaves of rose plants have stipules (leaflike appendages) at stalk bases and are most often compound.

The name “lily” indicates any of forty-five hundred species of the family Liliaceae. This is one of the largest, most important plant families in the order Liliales. The herbaceous flowering plants have beautiful, showy flowers.

True lilies, Liliaceae of the genus Lilium (one hundred species), are native to temperate areas of the Northern Hemisphere and are among the oldest of cultivated plants. Examples are Colchis, tiger, Madonna, and Easter lilies. Within the same family are onions, garlic, and asparagus. Also included in Liliales are tulips, daffodils, hyacinths, and amaryllis.

Among the eight thousand Liliales species are herbs, climbing shrubs, succulents, and trees. Their thick, fleshy stems grow from underground storage organs, and all have narrow, upright leaves with parallel veins. Most grow worldwide but flourish only in temperate and subtropical areas.

These perennials bloom once yearly and store food and water in scaly bulbs, corms, or rhizomes. Stems and leaves may be storage organs, too, and have thick bark to prevent water loss. Many plants in the group can carry out asexual reproduction via bulblets on parent bulbs or flower clusters (for example, garlic).

Tulips, Daffodils, and Irises


Tulips and irises share some characteristics. The Liliaceae genus Tulipa contains about one hundred tulip species. They are native to Asia and the eastern Mediterranean region, and thousands of tulip cultivars are popular garden flowers. A tulip plant produces two to three thick, blue-green leaves, clustered at its base.

Irises, also in the Liliales order, belong to the family Iridaceae, which includes some of the world’s most popular garden flowers. Irises are indigenous to the north temperate zone, Asia, and the Mediterranean region. “Iris” is the common name for spring-flowering, bulbous herbs.

The leaves of iris plants rise directly from the bulb or rootstock; they are very narrow, erect, and swordlike. Iris plants arise from rhizomes (stems underground) or bulbs and have large flowers. Iris, the Greek word for “rainbow,” refers to the flowers’ rainbow like color combinations.

Another interesting and popular group of flowering garden plants is daffodils, of the genus Narcissus. They are sold as bulbs. Daffodils are so popular that they have been widely hybridized. A daffodil plant usually produces five to six lance-shaped leaves grouped about the base of its stem. Each plant has one large flower.

Blooming Habits: Roses and Lilies

Wild rose plants have regular, single flowers, with five petals. In most cultivars double flowers, having petals numbered in multiples of five, are produced. The flower also has a calyx with five lobes, many stamens, and one or more carpels. Rose sprouts have two seed leaves, so the plants are eudicots. Flowers of most cultivars bear few seeds, and the majority of the mare sterile.

The number of seeds is small because in double roses, flower parts that would otherwise produce seeds become extra petals. Therefore, most roses are grown from cuttings. All new rose varieties begin as seedlings, raised from fertile seeds.

Lily flowers grow one per stalk or in clusters. In contrast to roses, they have six petal-like segments, causing the flowers to resemble trumpets or cups. The flowers range from white to shades of almost all other colors except blue.

Lily flowers all have three-chambered ovaries with nectaries between the chambers. They produce large,well-developed seeds which hold plenty of food-storage tissue and embryos.

Plants of most species are 1 to 4 feet (0.3 to 1.3 meters) tall, though a few grow up to 8 feet (nearly 3meters) tall. Lilies are usually raised from bulbs but can be grown from seed. Most species of these perennials bloom once, in July or August. However, flowering periods of some species begin in May or late autumn.

Blooming Habits: Tulips, Irises, and Daffodils

Tulip flowers can be single or double, and most, called “self-colored,” grow in a huge range of solid colors, from pure white to many shades of yellow, red, brown, and purple.

Some, called “broken tulips,” have varicolored flowers caused by a harmless virus carried by aphids. The garden tulip, introduced into Western Europe from Turkey in the 1600’s, is commercially cultivated most in the Netherlands and the United States, especially Michigan and Washington.

Bell-shaped lilies are usually solitary. They have three petals and three sepals, six stamens, and a triple ovary that ends in a three-lobed stigma. A tulip fruit holds numerous seeds, but many of the four thousand tulip cultivars can be propagated only via their scaly bulbs.

Iris flowers are more asymmetric than those of roses, lilies, or tulips. They possess six petal-like floral segments: three inner, erect standards forming an arch atop the flower and three outermost, drooping, often multicolored falls.

Aset of three petal-like stigmas also cover the stamens. Iris colors include white, yellow, bronze,mauve, purple, and red. Best known are rhizomatious bearded (German) irises, which have multi colored falls. These cultivars arose from European species.

They have stems up to 3 feet (1 meter) tall and yearly bear at least three flowers per plant. The twentieth century saw the development dwarf bearded irises and fragrant cultivars. The best-known beardless, rhizomatous irises are Japanese and Siberian irises,which have clusters of blooms. English and Spanish irises grow from bulbs.

Daffodils, the best-known members of the genus Narcissus, are indigenous to northern Europe and have been widely cultivated there and in North America. Usually daffodil plants grow to heights of about 1.5 feet (about 0.5 meter). Each plant produces one large blossom on its centrally located stem. The blossom has a corolla split into six lobes and a centrally located trumpet, the corona.

The corona is frilled at its edges, contains flower stamens, and leads to its pistil. The flowers were originally yellow; however, they have been hybridized into cultivars in which the trumpet and petals are often of contrasting yellows, whites, pinks, or oranges.

Rose and Lily Cultivation

Although found all over the world, roses grow best in mild climates, such as southern France and the U.S. Pacific coast. Roses’ excellent growth in many different kinds of soil and climate is a result of the availability of myriad cultivars.

A rose garden should be protected from cold wind and be exposed to sunlight for several hours a day. Deep, rich loam is best for roses, but most cultivars grow in sandy and gravelly soil.

The soil must be well drained. Roses are planted in spring, about 2 feet (0.6 meter) apart. In the United States, about sixty-five million commercial rose plants are cultivated yearly. About 35 percent are grown for cut flowers, and the rest are used in gardens or landscaping.

For the best growth, rose plants require severe pruning, which is adapted to the intended use of the flowers. Most varieties are grown by budding on under-stocks. Roses are susceptible to diseases such as rust and black-spot disease, so pests should be watched for and discouraged.

Lilies grow best in well-drained, deep, sandy loam, sheltered from winds and hot sunlight. Their bulbs are planted 6 or more inches (15 or more centimeters) underground, in late fall. This deep placement is used because they send out their roots well above the bulbs.

As soon as blooms wilt, their seed pods should be removed. Lilies can be made to bloom early by putting the bulbs in pots and covering them with peat moss or soil. When kept at 50 degrees Fahrenheit for two weeks and then stored at 60 degrees Fahrenheit, they bloom in three months.

Lilies are susceptible to a number of diseases. The most serious is mosaic, carried from plant to plant by aphids. Infected plants should be uprooted at once and burned to prevent an epidemic. A second severe disease of lilies is botryt is blight.

Tulip, Daffodil, and Iris Growth

Tulips are early bloomers, flowering in early spring;mid-season-bloomers; or late bloomers. Late bloomers are the largest group, with the widest range of growth habits and colors.

Tulips flourish in any good soil but, like roses, do best in well-drained loam. The bulbs are planted in autumn at depths of 6 or more inches. These perennial plants flower annually for a few years, but eventually flowering diminishes.

For best flower yields, after four to five years it is necessary to dig up bulbs after the flowers are gone and the foliage yellows. The bulbs should then be stored in a cool, dry place and replanted in autumn. Tulips are rarely attacked by garden pests.

Daffodil bulbs are planted in the fall, in loose soil, about 4 inches (10 centimeters) deep. The plants appear in mid-February. Their blossoms open in early April, announcing spring.

Like tulips, the plants flower well, annually, for a few years and then diminish. For best flower yields, it is useful to store the bulbs every four to five years in the manner described above for tulips.

Irises bloom from March to July and may be planted in the spring before blooming or in the autumn. These perennials give the best flowers if plants are replanted every four to five years to eliminate the problem of overcrowding. Bearded irises do best in sunny areas where the soil is not too rich, but beardless ones prefer damp, rich soil.

Iris diseases include crown rot, soft rot, and leaf spot. If the disease is serious, roots and soil may have to be treated. The worst iris insect enemy is the iris borer. Its larvae eat through leaves and roots, bringing on soft rot.