Rose gardening has a vocabulary of its own, and knowing the terms makes every other guide easier to follow – including ours. This glossary collects the words every rose gardener meets, from bud unions to hips, in plain English. Bookmark it and dip in whenever a term catches you out.
Organizations and Registration
All-American Rose Selections (AARS)
A nonprofit organization that recognized outstanding new roses after successful two-year trials in AARS test gardens around the country. The AARS award was one of the most trusted quality marks a new rose could earn; the program concluded in 2013, but AARS winners remain dependable garden performers.
International Registration Authority for Roses (ICRA)
Registering new rose varieties (cultivars) is the responsibility of the American Rose Society, which acts as the International Registration Authority for Roses. Registration keeps cultivar names unique worldwide so a rose sold under one name is the same plant everywhere.
Arboretum
An area landscaped to promote scientific study, education, and plant appreciation through tree, shrub, and herbaceous plantings. Many arboretums maintain dedicated rose gardens worth visiting for variety ideas.
Conservatory
An elaborate greenhouse with a glass roof for storing or conserving plants – historically how tender roses and other exotics were kept alive through winters.
The Plant Itself
Canes
The main stems of a rose plant. Canes carry the leaves, the flowering side shoots, and – in climbers – the whole vertical framework. Healthy green canes are the backbone of a productive rose; old woody ones are gradually replaced. See our guide to pruning climbing roses for how this works in practice.
Cultivar
A cultivated variety – a rose that humans selected and named because of specific traits. Rose cultivars number in the thousands, spanning every color and habit from tiny patio roses to huge ramblers.
Bud Union
The swollen knob at the base of a grafted rose where the flowering top was joined to the hardy rootstock. In mild climates it sits just above the soil; in cold climates gardeners bury it a couple of inches deep for winter protection.
Grafting and Own-Root
Grafted roses are joined onto a different rootstock for vigor or hardiness, while own-root roses grow on their own natural roots. Own-root roses can regrow true from the roots if the top dies back; grafted roses regrow from the rootstock instead – often as unwanted suckers.
Sucker
A shoot that grows from the rootstock below the bud union, often with different foliage from the named rose. Suckers steal energy and should be torn off – not cut – at the point of origin.
Hips
The fruits of the rose flower – rounded or urn-shaped, resembling cherries, and rich in vitamin C. When you deadhead, roses produce fewer hips but bloom more often; leave the last flush of autumn to set hips for winter color and bird food.
Growing and Classification
Deadheading
Removing spent blooms so the plant puts energy into new flowers instead of seed. It is the quickest way to keep repeat-flowering roses blooming through the season – the core of routine rose bush care.
Plant Hardiness Zones
Using average annual minimum winter temperature in 10-degree F bands, the contiguous United States and southern Canada are divided into 10 zones. Your zone tells you which roses survive your winter – we have guides to zones from the UK to Kentucky.
Taxonomy
The scientific classification of plants and animals by their natural relationships. Roses belong to the genus Rosa in the family Rosaceae – taxonomy is how the thousands of cultivars are organized and named.
With these terms in hand, rose books, labels, and nursery catalogs all read more clearly. Ready to put the vocabulary to work? Start with tips for rose planting, or if your roses are already in the ground, our organic rose gardening guide covers their care from soil up.