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Mom may want diamonds, iPads, or even just one lousy phone call for Mother's Day. But chances are, she's getting flowers.

Two-thirds of shoppers plan to buy flowers this year, according to the National Retail Federation. Second only to greeting cards, they are Mother's Day's go-to gift. "Flowers have always reigned as one of the top gifts," says NRF spokeswoman Kathy Grannis. They're a safe bet -- what woman doesn't love flowers? -- as well as an easy add-on for picks like jewelry, dinner out or a spa gift certificate, she says. Those buying only flowers will spend an average $27.17, up 6% from last year, while people buying a bouquet and another gift will spend $18.08 on the bloom portion, up 8%.

Shoppers may find even higher prices if they wait to order. Sales tend to level off as Mother's Day approaches, leaving shoppers paying more for either flowers or delivery -- or both, says Sok Verdery, chief executive for CouponShack.com. This year, he says, more are charging premium delivery fees of up to $20 for last-minute orders.

But there's a bright spot for shoppers: unlike red roses for Valentine's Day, there's no signature flower for Mother's Day, meaning you shouldn't expect to pay elevated prices compared with other times of the year, say experts. "We haven't heard anything about rising costs for Mother's Day," says Jennifer Sparks, a spokeswoman for the Society of American Florists. Here are some of recommendations for getting a better deal on flowers this year:

Order early

Price isn't the only reason to order early. Experts say the number of delivery spots dwindle, too, which may lock consumers out of an actual Mother's Day delivery. An early order also increases the chances of getting the bouquet you want, says Eileen Johnson, the director of Flower School New York. More notice gives florists leeway to get the blooms one orders, instead of substituting other types or colors. Last-minute orderers must make do with what's already on hand. "Never wait until Sunday morning, or you are likely to be buying leftovers," she says.

Hunt for sales

Coupon codes are prevalent among flower-delivery sites, Grannis says. Some are good only on particular bouquets or categories -- as in, birthday blooms and not Mother's Day ones -- so check the fine print before clicking through. FTD.com currently has an offer for 20% off most orders; ProFlowers.com, up to 50% off specific arrangements. Check daily-deal sites, too: $30 worth of flowers at Teleflora.com is currently $15 via PlumDistrict.com. Deal vouchers usually can't be combined with coupon codes, however.

Compare total costs

Those enticing sales are usually just a starting price, Verdery warns. Some vendors charge extra for a vase, and then there are fees for shipping or delivery. Some also tack on extra charges of up to $20 for arrival on popular days -- namely, the weekend of Mother's Day -- or for guaranteed arrival by a certain time of day, he says. (Sparks says local florists typically don't charge such premiums, but there may be a discount for having an arrangement delivered before the holiday weekend.)

Look beyond pictures

What you order online isn't always exactly what you get. Florist-filled orders may require different vases or flowers, Spark says, and grower-shipped ones usually arrive un-arranged in a box. "Make sure that you know where the bouquet is coming from, and what it will look like when it arrives," she says. Consumers counting on say, sunflowers or an all-pink bouquet may want to call the florist or make a note in the online order highlighting that request.

Consider DIY options

Even $5 or $10 in blooms from a supermarket or farmer's market can look luxe. "Generally I would suggest that you go with pastel flowers all in the same palette," says Johnson. That makes it easy to arrange. Another idea for novices: go big, with two or three bunches of the same kind and color of flower.