Bougainvilleas follow two unbreakable rules that gardeners would be wise to pay attention to.
First, they go dormant in very cold weather.
"Their response to freezing temperatures is they drop their leaves, drop their flowers and they just rest for three or four months," says Lesley Mansur, owner of Great Gardens landscape design.
The more mature the South American native is, the better it can handle the cold. But every year at least some of the thorny branches, green leaves, tiny flowers and vividly colored brachs die back.
Because of this rule, "bougainvillea are for the year-rounders, not for the winter visitors," says Elizabeth Przygoda-Montgomery, owner of Boxhill Design. The plant, which comes as a vine or bush, just won't provide spectacular, if any, color in the winter.
Rule no. 2: The less you fuss over a bougainvillea, the better it will produce those brachs, the leaves that change into papery bright whites, pale pinks and oranges and deep reds and magentas.
"They're a tough plant," says Mansur. "They don't need a lot of TLC."
In fact, overwatering makes them lazy. "If they get too much irrigation, they become very complacent and they don't bother to bloom," she says.
Instead, grow bougainvillea with minimal water, sparse fertilizer and at least six hours of direct sun a day.
The two landscape designers and Beth Hargrove, owner of Rillito Nursery & Garden Center, offer more tips for growing bougainvillea.
• The Barbara Karst is the hardiest bougainvillea cultivar and does well in Tucson. Others are not as cold hardy.
• Plant soon after the last frost so that they have a good nine to 10 months to get established before the next cold snap. Hargrove suggests a shot of fertilizer at the beginning to get it going.
• Plant near a west, south or southwest wall that gets direct sun for most of the day. The wall helps to provide more warmth in cooler months.
• Bougainvilleas are messy plants. Place them away from pools or areas that can get stained from crushed wet brachs.
• Gently handle the root ball when transplanting from the store container to the ground. Pop it out of the container and straight into the hole or pot.
• Irrigate once a week until established. Then cut back to occasional watering.
• Don't prune after it dies back until you see new growth coming in. Then cut to just above the new growth where the stem or branch has a reddish hue.
Contact Tucson freelance writer Elena Acoba at email@example.com