Rootstock in the context of "Garden roses"

In botany, the term perennial (per- + -ennial, "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also loosely used to distinguish plants with little or no woody growth (secondary growth in girth) from trees and shrubs, which are also technically perennials. An estimated 94% of plant species are perennials.

Perennials (especially small flowering plants) that grow and bloom over the spring and summer, die back every autumn and winter, and then return in the spring from their rootstock or other overwintering structure, are known as herbaceous perennials. However, depending on the rigours of the local climate (temperature, moisture, organic content in the soil, microorganisms), a plant that is a perennial in its native habitat, may be treated by a gardener as an annual and planted out every year, from seed, from cuttings, or from divisions. Tomato vines, for example, live several years in their natural tropical/ subtropical habitat but are grown as annuals in temperate regions because their above-ground biomass does not survive the winter.

Grafting or graftage is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion (/ˈsaɪən/) while the lower part is called the rootstock. The success of this joining requires that the vascular tissues grow together. The natural equivalent of this process is inosculation. The technique is most commonly used in asexual propagation of commercially grown plants for the horticultural and agricultural trades. The scion is typically joined to the rootstock at the soil line; however, top work grafting may occur far above this line, leaving an understock consisting of the lower part of the trunk and the root system.

In most cases, the stock or rootstock is selected for its roots and the scion is selected for its stems, leaves, flowers, or fruits. The scion contains the desired genes to be duplicated in future production by the grafted plant.

An apple is the round, edible fruit of an apple tree (Malus spp.). Fruit trees of the orchard or domestic apple (Malus domestica), the most widely grown in the genus, are cultivated worldwide. The tree originated in Central Asia, where its wild ancestor, Malus sieversii, is still found. Apples have been grown for thousands of years in Eurasia before they were introduced to North America by European colonists. Apples have cultural significance in many mythologies (including Norse and Greek) and religions (such as Christianity in Europe).

Apples grown from seeds tend to be very different from those of their parents, and the resultant fruit frequently lacks desired characteristics. For commercial purposes, including botanical evaluation, apple cultivars are propagated by clonal grafting onto rootstocks. Apple trees grown without rootstocks tend to be larger and much slower to fruit after planting. Rootstocks are used to control the speed of growth and the size of the resulting tree, allowing for easier harvesting.

In horticulture, a graft-chimaera may arise in grafting at the point of contact between rootstock and scion and will have properties intermediate between those of its "parents". Unlike graft hybrids, a graft-chimaera is not a true hybrid but a mixture of cells, each with the genotype of one of its "parents": it is a chimaera. Hence, the once widely used term "graft-hybrid" is inaccurate for a graft-chimaera.

Propagation is by cloning only. In practice graft-chimaeras are not noted for their stability and may easily revert to one of the "parents".

Canaiolo (Italian pronunciation: [kanaˈjɔːlo]), also called Canaiolo nero or Uva Canina, is a red Italian wine grape grown through Central Italy but is most noted in Tuscany. Other regions with plantings of Canaiolo include Lazio, Marche and Sardegna. In Umbria a white berried mutation known as Canaiolo bianco exists. Together with Sangiovese and Colorino it is often used to create Chianti wine and is an important but secondary component of Vino Nobile di Montepulciano. In the history of Chianti it has been a key component blend and during the 18th century may have been the primarily grape used in higher percentage than Sangiovese. Part of its popularity may have been the grape's ability to partially dry out without rotting for use in the governo method of prolonging fermentation. In the 19th century, the Chianti recipe of Bettino Ricasoli called for Canaiolo to play a supporting role to Sangiovese, adding fruitiness and softening tannins without detracting from the wine's aromas. In the aftermath of the phylloxera epidemic, the Canaiolo vines did not take well to grafting onto new American rootstock and the grape began to steadily fall out of favor. As of 2006, total plantings of Canaiolo throughout Italy dropped to under 7,410 acres (3,000 hectares). Today there are renewed efforts by Tuscan winemakers to find better clonal selections and re-introduce the variety into popular usage.

A white sub-variety exists, known as Canaiolo bianco, which is a permitted grape variety in the Umbrian wine region of Orvieto where is known as Drupeggio. In recent years plantings have been declining.