Few summer flowers earn a spot on the porch year after year quite like the geranium. With their bright clusters of red, pink, salmon, and white blooms set against softly scalloped leaves, these classic container plants have anchored window boxes and patio pots for generations. The best part is how forgiving they are. Give a geranium decent light, well-draining soil, and a sensible watering routine, and it will reward you with color from late spring straight through to the first frost.
This guide walks through everything that keeps a geranium thriving, from picking the right type to feeding, deadheading, troubleshooting yellow leaves, and carrying your favorite plants through winter so you do not have to buy new ones every spring.
What Most Gardeners Call a Geranium Is Actually a Pelargonium
Here is the quirk that trips up almost everyone: the cheerful bedding plant sold as a “geranium” at the garden center is not a true geranium at all. It belongs to the genus Pelargonium, native to the hot, dry climates of southern Africa and Australia. The name comes from the Greek pelargos, meaning “stork,” a nod to the long, beak-like shape of the seedpods.
True geraniums (genus Geranium), often called hardy geraniums or cranesbills, are a different plant entirely. Both belong to the Geraniaceae family, but their care needs diverge sharply, and knowing which one you have changes everything about how you grow it.
The practical difference comes down to cold tolerance:
- Tender geraniums (Pelargonium) are the showy bedding and container plants. They are technically perennials, but they survive winter outdoors only in USDA zones 10 and 11. Everywhere colder, gardeners grow them as annuals or bring them inside before frost.
- Hardy geraniums (Geranium / cranesbill) are true perennials, surviving to roughly -20 degrees Fahrenheit. You cut them back in fall and they return on their own each spring.
If your plant has big, rounded leaf zones and bold ball-shaped flower clusters, you almost certainly have a pelargonium, and the rest of this guide is for you.
Types of Geraniums to Know Before You Buy
There are several distinct kinds of tender geranium, and matching the type to your spot makes all the difference.
- Zonal geraniums (Pelargonium x hortorum) are the most familiar form, named for the darker bands or “zones” of color on their leaves. They grow upright and bushy, bloom in pink, red, salmon, and white, and are the workhorses of beds and containers.
- Ivy geraniums (Pelargonium peltatum) have glossy, ivy-shaped leaves and long, trailing stems that spill beautifully over the edges of hanging baskets and window boxes.
- Regal or Martha Washington geraniums (Pelargonium x domesticum) carry large, ruffled, often patterned flowers. They are the showiest of the group but also the fussiest, preferring cool conditions over heat, which makes them popular as indoor flowering pot plants.
- Scented-leaf geraniums are grown for their foliage rather than their modest flowers. Brush or rub the leaves and you release fragrances of rose, lemon, mint, apple, or citronella. The leaves of many are edible and used in teas, jellies, and potpourri.
- Seed and interspecific types are compact, free-flowering forms grown from seed. Their blooms are smaller but more numerous, and many “shatter,” shedding spent petals on their own so you do not need to deadhead.
How Much Light and Warmth Geraniums Need
Geraniums are sun lovers. Aim for 4 to 8 hours of direct sunlight per day, which is the threshold for strong, continuous flowering. In cooler climates they will happily take full sun all day. In regions with brutal summers, give them a few hours of afternoon shade so the heat does not stall their growth or scorch the foliage.
Temperature matters just as much as light. Coming from warm origins, geraniums grow best with daytime temperatures in the 65 to 75 degree Fahrenheit range and nights around 55 to 65 degrees. They essentially stop growing once temperatures dip near 50 degrees Fahrenheit or climb above 85, so do not be alarmed if a midsummer heat wave puts blooming on pause.
Plant them outdoors only after all danger of frost has passed and the soil has warmed. Indoors, geraniums need a bright south- or west-facing window to keep flowering, plus daytime warmth around 65 to 70 degrees and cooler nights near 55.
Soil, Spacing, and Planting
Geraniums are not picky about much, but they are unforgiving about drainage. They will rot in heavy, soggy, or compacted clay, so the goal is loose, well-draining, fertile soil rich in organic matter. If your garden soil runs heavy, work in compost, peat, or perlite before planting. In containers, reach for a light, well-draining potting mix rather than dense garden soil, and choose pots with drainage holes so water never pools at the roots.
The easiest way to start is with transplants, which fill garden centers every spring. Set plants at the same depth they grew in their nursery pots and space them 8 to 12 inches apart. That spacing is not just about looks; good air circulation between plants is one of your best defenses against the fungal diseases geraniums are prone to. After planting, a layer of mulch helps the soil hold moisture and stay cooler through hot weather.
For containers, pick a generously sized pot. A larger volume of soil holds more water and resists the rapid wilting that small pots suffer in summer heat. One or two plants in a 12-inch pot is a reliable starting point.
Watering Geraniums Without Drowning Them
Geraniums tolerate dry soil far better than wet, and overwatering does more damage than the occasional missed watering. The reliable test is your finger: when the top 1 to 2 inches of soil feels dry, water thoroughly until it runs from the drainage holes, then let the soil dry out somewhat before the next round.
In peak summer heat, outdoor potted geraniums may need water every day because containers dry out fast. Plants in the ground need at least an inch of water per week during hot spells. Whatever the schedule, water at the soil line and keep the foliage dry. Splashing the leaves invites the very diseases that plague this plant. Indoors and over winter, watering needs drop dramatically, sometimes to only every couple of weeks, because the plant slows down in lower light.
Feeding for Steady Blooms
Geraniums put on a long flowering display, and that takes fuel, especially when they are grown as annuals in containers. Feed them with a balanced water-soluble fertilizer or a formula such as 5-10-5 or 10-20-10 every four to six weeks through the active growing season. If you started with a potting mix that already contains fertilizer, you can stretch that interval at the beginning of the season.
One important caution: more is not better. Excess nitrogen pushes lush green growth at the expense of flowers, so resist the urge to overfeed a plant that is leafy but stingy with blooms.
Deadheading and Pinching for More Flowers
Geraniums are low-maintenance, but two simple habits keep them looking their best. Deadhead spent flower clusters by snapping the stem off cleanly below the joint where it meets the main stem, rather than just plucking the faded petals. Removing old blooms redirects the plant’s energy into producing new ones, extending the show all summer. (Seed-grown and self-cleaning types like ‘Balcon’ shed their own spent flowers, so you can skip this.)
When stems start to stretch out and look bare and leggy, pinch back the growing tips. This encourages the plant to branch and fill out into a fuller, bushier shape. Leggy growth is also a signal worth reading: it usually means the plant wants more light.
Common Problems, Pests, and Diseases
Most geranium trouble traces back to too much moisture, too little light, or poor air circulation. Knowing the symptoms lets you act before a problem spreads.
Why are the leaves turning yellow? This is the single most common geranium complaint, and the pattern tells you the cause. Lower leaves yellowing first often points to a nitrogen deficiency, as the plant pulls nutrients from old growth. Widespread yellowing with soft, dropping leaves usually means overwatering and the beginnings of root rot, so let the soil dry and ease off the watering can. Yellowing on a plant recently moved indoors is typically a light-deficiency response, as the plant sheds its sun-adapted leaves. Frost exposure and even herbicide drift from a neighbor’s yard can yellow leaves too.
Why is it not blooming? Three culprits dominate: too much nitrogen, too little light, and too small a difference between day and night temperatures. Cut back on feeding, move the plant into brighter light, and let nights run cooler than days.
Diseases are nearly all moisture-driven. Botrytis (gray mold) blights flowers and leaves in cool, damp conditions; bacterial blight causes leaf spots and stem rot; and zonal types are prone to pelargonium rust, recognizable as brown spots on the undersides of leaves. Oedema, those small corky bumps on the leaves, comes from overwatering combined with low light. The fix for almost all of these is the same: space plants for airflow, water at the base, keep foliage dry, give them enough sun, and promptly remove any infected leaves or plants.
Pests include aphids, spider mites, whiteflies, mealybugs, and caterpillars, and they are far more troublesome on indoor plants than outdoor ones. Watch for sticky honeydew or fine webbing, pick off small infestations by hand, and treat larger ones with insecticidal soap.
A quick myth to retire: the so-called “citronella” or “mosquito plant” geranium is widely sold as a natural mosquito repellent, but it has never been proven to keep mosquitoes away. Grow it for its pleasant scent, not pest control.
Are Geraniums Toxic to Pets?
This is a detail most growing guides skip, and it matters if you share your home with animals. Tender geraniums (Pelargonium) are toxic to dogs and cats. All parts of the plant contain low levels of two compounds, geraniol and linalool, and ingestion can cause vomiting, loss of appetite, lethargy, and skin irritation. Cats are especially sensitive. Keep pots out of reach of curious pets, and if you suspect your animal has chewed on a plant, contact your veterinarian.
Note the species split here too: the hardy, true Geranium (cranesbill) is generally not considered toxic to pets. The toxicity concern applies specifically to the Pelargonium types.
How to Propagate Geraniums
Multiplying your geraniums is easy and cheap, and there are two routes.
From cuttings is the most reliable method and the only way to guarantee a new plant identical to the parent. Take a 4- to 5-inch cutting from a healthy, non-flowering shoot, cutting just below a node. Strip the lower leaves, pinch off any flower buds, and let the cut end dry for an hour or two. Then push it into gritty, well-draining potting mix or root it in a glass of water before potting up. Keep it warm, bright, and out of harsh direct sun until roots develop. Take cuttings in early summer in warm climates, or in late summer to early fall if you grow geraniums as annuals and want plants for next year.
From seed is slower and works mainly for single-flowered, seed-grown varieties. Start seeds indoors 8 to 10 weeks before your last frost date, since the plants mature slowly, then transplant outdoors once frost has passed.
How to Overwinter Geraniums
Because tender geraniums cannot survive a cold winter outdoors, gardeners in most regions either treat them as annuals or carry them over indoors. Overwintering is more economical than buying new plants each spring, and you have three proven methods to choose from.
- Take cuttings. In fall, root cuttings from your best plants and grow the small new plants on a sunny windowsill through winter. This saves your favorite varieties in the least amount of space.
- Keep them growing as houseplants. Before the first frost, dig up or pot the plant, cut it back by about a third to its top 6 inches, remove damaged leaves, and set it in a cool, bright window. Water lightly through winter; the plant stays semi-active rather than fully dormant. Keep it away from radiators and other heat sources.
- Store them dormant. For the most vigorous comeback the following year, let the plant go dormant. Pot it up and place it somewhere cool, dark, and frost-free such as a basement or attached garage, or hang the bare-rooted plant upside down in a cool spot. Water only once a month. In early spring, cut back the top growth hard, move it to a sunny window, resume regular watering, and feed once new growth appears.
Whichever method you choose, wait until all danger of frost has passed in spring before moving your overwintered geraniums back outdoors, then give them a trim and a liquid feed to kick off a new season of bloom.
With the right light, restrained watering, regular deadheading, and a plan for winter, a single geranium can stay with your garden for years. Pick the type that suits your space, give it room to breathe, and you will have dependable summer color from a plant that asks very little in return. Start with one healthy transplant this spring and you may never need to buy another.