What is a “Geranium?”
Many gardeners are confused by the term “Geranium”, and with good reason.
The enormously popular and familiar red flowering annual plants that are a staple in Grandma’s window box have been referred to for generations as Geraniums. While Geranium is the common name for these annual plants, their botanical name is actually Pelargonium. Pelargoniums are distantly – but not closely – related to true Geraniums, which are hardy perennial plants.
To avoid confusion, we usually refer to Pelargoniums as “annual Geraniums” and true Geraniums as “hardy/perennial Geraniums”.
Showy Autumn Foliage
Many perennial Geraniums develop quite showy brightly colored foliage in autumn.
Reliable & Adaptable
For the most part perennial Geraniums are extremely reliable plants that are adaptable to a wide range of light and soil conditions, although most are ideally suited to loamy soil in light shade. As a group, they tend to be avoided by deer & rabbits and are disease resistant, long blooming, well behaved and attractive.
There are dozens of species and cultivars of perennial Geraniums.
Here at Johnson’s Gardens we grow the following types, which we believe to be some of the best available:
Geranium maculatum (Wild Geranium)
This is our Wisconsin native Geranium. It is naturally found growing in humus rich lightly shaded woodland areas but is adaptable to a wide range of growing conditions.
It bears lavender-pink flowers in spring and early summer on lax 12”-24” stems over lobed foliage and increases slowly to form a mature clump 12”-24” wide.
Self-sows modestly if allowed to go to seed.
Extremely hardy (to zone 3) and very reliable.
Geranium macrorrhizum (“Bigroot Geranium”)
Are you looking for a great groundcover for a dry, shaded site? Geranium macrorrhizum fits the bill.
This highly adaptable plant will thrive in diverse growing conditions ranging from sun to shade and including dry shade such as that found under maples. Its large soft green leaves form a 12″-18″ mound that remains attractive throughout the entire growing season. The leaves emit a pungent scent when crushed ( historically this plant was valued for its oil content ), which makes it unattractive to deer & rabbits. In spring it bears clusters of bright magenta-pink flowers. Once touched by frost in autumn the leaves take on hues of bright red and orange. Slowly increases by rootstock as well as seeding to form large colonies.
Overall a great plant that performs beautifully throughout the growing season in even the most challenging of sites.
Geranium x cantabrigiense ‘Karmina’
The result of a cross between Bigroot Geranium and the petite alpine Geranium dalmaticum, this plant combines the best of both parents.
Intermediate in size, it forms a dense, tidy mound of glossy lobed foliage. Bright pink flowers are borne in profusion in early summer, with sporadic bloom throughout the season. Its aromatic foliage is resistant to deer browsing and in autumn the leaves take on brilliant red hues. ‘Karmina’ is an excellent choice for the front of the border and is frequently used as an edging plant.
Tolerant of sun or shade but happiest in partial shade.
Mature size: 6”-10” tall x 15″-18” wide. Hardy to zone 4.
When she’s happy, ‘Rozanne’ is a stunner. This plant bears violet blue flowers, with striking blue stamens rising out of white centers, on vining stems all summer long. It is certainly the longest blooming perennial geranium and may come close to holding the record for length of bloom among all perennials. The foliage is deeply lobed and carried on vining stems that reach 18”-24” in length and 15”-18” tall.
The perfect perennial, right? Unfortunately, Rozanne has one downfall. While technically hardy to zone 5, she is temperamental and exhibits unpredictable perenniality in some sites. Well drained winter soil does seem to be helpful and winter mulch may benefit the plant as well.
Given the outstanding length of bloom and notable color that ‘Rozanne’ provides, many gardeners are willing to take the chance. As a result, this plant continues to be one of the most popular perennials on the market today.