Every Scaevola species is technically a perennial, but whether yours behaves like one depends almost entirely on where you live. In frost-free climates, the popular garden species Scaevola aemula grows as a spreading evergreen that returns year after year. Anywhere a hard frost hits, it dies to the ground, which is why nurseries across most of North America and Europe sell it as a warm-season annual.
An Australian Genus with Global Reach
Scaevola belongs to the Goodeniaceae family and contains well over 100 species, the vast majority of which are native to Australia. Molecular studies confirm that the genus originated on that continent, with at least six separate dispersal events carrying different lineages outward across the Pacific and Indian Ocean basins.1PubMed. Phylogenetics of the genus Scaevola (Goodeniaceae): implication for dispersal patterns across the Pacific Basin and colonization of the Hawaiian Islands Two of those dispersal events were especially consequential, producing large radiations that include the two best-known widespread species: Scaevola taccada, which colonized tropical and subtropical coastlines around the world, and Scaevola plumieri, found along Atlantic shores in both the Americas and West Africa.
For gardeners, two species dominate the conversation. Scaevola aemula is the one you see in hanging baskets and window boxes at garden centers, bred into compact cultivars with names like “New Wonder,” “Whirlwind Blue,” and “Bombay Pink.” Scaevola taccada is the tough coastal shrub you encounter on tropical beaches from Hawaii to East Africa. Both are perennials in nature, but their climate tolerances differ enough that the practical answer to “will it come back next year?” depends on which species you have and how cold your winters get.
Scaevola aemula in the Garden
Scaevola aemula, commonly called fan flower for its distinctively shaped blooms, is native to sandy and coastal areas of southern and eastern Australia. In its home range, it grows as a low, spreading groundcover or trailing perennial, rooting along stems as it goes. The plant flowers prolifically from late spring through fall, producing small fan-shaped blooms in shades of blue, purple, pink, or white. It handles heat, humidity, and lean soil with very little fuss, which is why it became a staple of the commercial bedding-plant industry in the 1990s.
The catch is cold. Scaevola aemula has essentially no frost tolerance. It thrives in USDA hardiness zones 10 and 11, where winter lows rarely dip below about 1°C (around 35°F). In zone 9, it sometimes survives mild winters, especially if planted in a sheltered microclimate against a south-facing wall, but a single night of hard frost can destroy the entire plant. In zones 8 and colder, there is no realistic chance it will overwinter outdoors. That is why most gardeners treat it as an annual, buying fresh plants each spring and composting the remains after the first frost.
This does not mean the plant itself is genetically an annual. It has no built-in life-cycle clock that tells it to set seed and die after one season. Given warm enough conditions, the same individual can live for years, growing woodier at the base and spreading over a surprisingly large area. Gardeners in subtropical parts of Florida, coastal Southern California, and parts of Australia report fan flower persisting and expanding for three or more seasons. The distinction matters because it affects how you think about the plant: if you can protect it from cold, you can keep it.
Scaevola taccada and Tropical Permanence
Scaevola taccada occupies a completely different niche. It is a coastal evergreen shrub that grows up to three or four meters tall, with thick, fleshy leaves that tolerate salt spray, sandy substrate, and full tropical sun. Phylogeographic analysis indicates it originated in Australia before spreading across the Indo-Pacific, and its range now extends along tropical and subtropical coastlines worldwide.2Journal of Systematics and Evolution. Deciphering the global phylogeography of a coastal shrub (Scaevola taccada) reveals the influence of multiple forces on contemporary population structure In Hawaii, where it is known as naupaka kahakai, it is one of the most recognizable native coastal plants.
Unlike the garden-center fan flower, S. taccada is unambiguously a perennial wherever it grows. It blooms throughout the year, with flowering intensifying during the wet season, and its flowers are bisexual and self-compatible, though they primarily cross-pollinate with the help of bees and wasps.3Academia.edu. Pollination ecology of the coastal pantropical hermaphroditic shrub Scaevola taccada (Goodeniaceae) The plant’s tolerance for salinity and its ability to stabilize dunes make it an important species in coastal restoration projects. However, it is strictly tropical: freezing temperatures will kill it, so it is not a realistic garden plant outside of USDA zones 10b through 13.
If you have encountered Scaevola on a beach vacation in the tropics and wondered whether you could grow it at home in a temperate climate, the honest answer for S. taccada is almost certainly no, unless home is somewhere like South Florida, coastal Hawaii, or a frost-free stretch of the Caribbean. It is far too large and sun-hungry for a windowsill, and it does not adapt well to indoor container life the way smaller species do.
What Cold Hardiness Actually Means for Scaevola
Cold hardiness in plants is not a simple threshold. A plant rated to zone 10 does not die the instant the thermometer touches 0°C and then live happily at 1°C. The duration of a cold snap, the moisture level in the soil, the wind chill, and whether the plant has had time to acclimate all play roles. For Scaevola aemula, a brief dip to freezing on a still night with dry soil might leave the stems damaged but the crown alive, while a prolonged freeze with wet roots will kill the plant outright.
This is why gardeners in borderline zones (roughly 9b to 10a) report wildly inconsistent results. In a mild winter, their fan flower comes back from the roots in spring. In a harder winter the following year, it does not. If you live in one of these borderline areas, you can improve your odds by mulching the root zone heavily in late fall, choosing a planting spot with excellent drainage, and avoiding overhead irrigation during cold spells. But you should still keep a plan B in mind, because a single Arctic air mass pushing unusually far south can undo years of careful siting.
For gardeners in zone 8 and colder, the calculus is simpler. Scaevola will not survive your winter outdoors, period. Your options are to treat it as an annual (buy, enjoy, compost) or to overwinter it indoors, which is entirely doable if you have the right conditions.
How Scaevola Handles Heat
If cold is Scaevola’s nemesis, heat is closer to its comfort zone, though there are limits. Research on Scaevola aemula seedlings exposed to elevated temperatures showed that the plant ramps up production of photosynthetic pigments in response to heat stress. At moderately high temperatures (around 35°C during the day, 27°C at night), pigment concentrations in the leaves more than doubled compared to control plants and stayed elevated over multiple days.4South African Journal of Botany. Physiological responses of Scaevola aemula seedlings under high temperature stress At more extreme heat (40°C days, 30°C nights), the same initial boost occurred, but by the third day the plant’s response had leveled off and pigment levels were no longer significantly different from controls.
What this means in practical terms is that fan flower handles a hot summer well, which lines up with its reputation as a heat-loving bedding plant. It continues to flower and look healthy through the kind of sustained heat that wilts petunias and impatiens. But there is a ceiling. In regions where daytime highs routinely exceed 40°C for days on end, Scaevola can begin to struggle. Gardeners in the hottest parts of the American Southwest or interior Australia sometimes notice that fan flower slows its blooming or looks washed out during the worst of summer. Providing afternoon shade and consistent moisture helps, but the plant’s heat tolerance, while impressive, is not infinite.
Overwintering Scaevola Indoors
Because Scaevola aemula is a true perennial, you can keep the same plant going for multiple years by bringing it inside before frost. The process works best with container-grown plants. If your fan flower is in a hanging basket or pot, move it indoors when nighttime temperatures start approaching 5°C. If it is planted in the ground, you can take cuttings in late summer and root them in moist potting mix; they root readily from stem-tip cuttings, and a few weeks under a humidity dome is usually all it takes.
Indoors, the plant needs bright light. A south-facing window is the minimum; supplemental grow lights make a real difference. Fan flower does not go fully dormant, but its growth slows considerably in winter, so you should cut back on watering and stop fertilizing until spring. Expect it to look ragged by February. Leggy stems, some leaf drop, and a general air of unhappiness are normal for a plant that evolved for Australian sunshine and is enduring a Michigan winter under a grow light. That is fine. In spring, give it a hard pruning, move it back outside after the last frost, resume feeding, and it will flush out with new growth quickly.
Whether overwintering is worth the trouble depends on your situation. If you grow a common cultivar that costs a few dollars at the garden center each spring, the effort of indoor care may not make sense. But if you have a favorite plant with especially good color, or a large specimen that took a couple of seasons to reach an impressive size, bringing it through winter lets you start the next season with a bigger, more established plant than anything you could buy.
Growing Scaevola as a Deliberate Annual
Plenty of gardeners in cold climates choose to grow Scaevola aemula as a one-season annual and are perfectly happy with the arrangement. The plant fills a specific role that few other annuals fill as well: a trailing, heat-tolerant, low-maintenance bloomer for containers, hanging baskets, and the edges of raised beds. It pairs naturally with other warm-season trailing plants and upright annuals in mixed containers, and its fan-shaped flowers have an unusual look that reads as more interesting than a standard petunia.
When grown as an annual, Scaevola needs full sun (at least six hours), well-drained potting mix, and regular feeding. It is not especially heavy-feeding compared to something like a calibrachoa, but a slow-release granular fertilizer at planting plus a liquid feed every couple of weeks during peak bloom keeps it looking its best. One of its genuine advantages over many other basket plants is that it does not need deadheading. Spent flowers drop cleanly, and new ones replace them without any intervention. That trait alone makes it a favorite for people who want color without constant grooming.
Scaevola is also relatively pest-free. Aphids and whiteflies occasionally show up, but the plant does not attract them the way some other bedding plants do. Root rot from overwatering is a bigger risk than any insect. If you keep the soil consistently moist but never soggy, and if your container has good drainage holes, most problems simply never materialize.
Other Species and the Hawaiian Connection
Beyond S. aemula and S. taccada, the genus contains a surprising diversity of growth forms. Some Australian species are small woody shrubs; others are creeping groundcovers or even semi-succulent coastal plants. A handful of species have radiated into unique forms in the Hawaiian Islands, where they evolved in isolation after long-distance dispersal from the ancestral Australian range.1PubMed. Phylogenetics of the genus Scaevola (Goodeniaceae): implication for dispersal patterns across the Pacific Basin and colonization of the Hawaiian Islands Hawaii is home to several endemic Scaevola species that occupy mountain habitats, shrublands, and dry forests, looking nothing like either the beach-dwelling naupaka or the garden-center fan flower.
The Hawaiian species carry cultural significance as well. In Hawaiian tradition, the half-flower shape of naupaka is explained by a love story: two separated lovers are each represented by one half of the flower, one on the mountain (naupaka kuahiwi) and one on the beach (naupaka kahakai). The mountain naupaka species are distinct from S. taccada and are in some cases quite rare, threatened by habitat loss and invasive species. Conservation efforts in Hawaii focus on protecting remaining populations and restoring habitat, which is a very different relationship with the genus than the one a gardener in Ohio has with a hanging basket of “Whirlwind Blue.”
When Scaevola Becomes Invasive
A trait that makes a plant a great perennial in one place can make it a problem in another. Scaevola taccada, thanks to its salt tolerance, vigorous growth, and bird-dispersed fruits, has become invasive in parts of the Caribbean, coastal Florida, and several Pacific island groups outside its native range. It can form dense thickets that shade out native coastal vegetation, altering dune ecology and reducing habitat for native plants and nesting sea turtles. In southern Florida, S. taccada is classified as a Category II invasive by the Florida Exotic Pest Plant Council, meaning it has spread in the wild but is not yet considered as damaging as Category I species.
Scaevola aemula, by contrast, has not shown significant invasive tendencies. It produces far less seed than S. taccada, spreads mainly by rooting along its stems rather than by long-distance seed dispersal, and dies at the first frost in any temperate zone. If you are gardening in a tropical or subtropical area and considering planting Scaevola, checking your local invasive-species list for S. taccada before planting is worth the few minutes it takes. The garden fan flower, S. aemula, is generally safe to plant anywhere and is the species you will find at mainstream nurseries.
Propagation and Keeping Your Genetics Going
If you find a Scaevola aemula cultivar you love and want to keep it going from year to year without buying new plants, stem-tip cuttings are the simplest method. Take cuttings about 8 to 10 centimeters long from non-flowering shoot tips, strip the lower leaves, dip the cut end in rooting hormone, and stick them in a well-drained mix of perlite and peat. Under a clear plastic cover to hold humidity, they typically root within two to three weeks. Late summer is the ideal time if your goal is overwintering, because it gives the cuttings time to establish roots before you move them inside.
Growing Scaevola from seed is possible but much less common. Most garden cultivars are vegetatively propagated and may not come true from seed even if you manage to collect it. S. taccada, on the other hand, produces buoyant fruits that float in seawater for months, which is how it colonized coastlines across the tropics. Those fruits germinate readily in warm, moist conditions, but the resulting plants are full-sized shrubs, not compact basket plants. Unless you have space for a large tropical hedge, cuttings of S. aemula are the more practical route for home gardeners.