See http://gardening.about.com/od/plantprofiles/p/Snapdragons.htm
Latin Name:
Antirrhinum majus
Common Name:
Snapdragon, Dog's/ Lion's/Toad's Mo
Overview:
Snapdragons have stalks of brightly colored flowers that are especially profuse in cooler weather. The plants start blooming at the bottom of the stalk and work their way up. The common names all derive from the way the flowers resemble opening mouths, when they are pressed on their sides. The flowers are snapped shut and require more pressure to open than a honeybee can provide, so snapdragons rely on heavier bumble bees for their pollination
Description:
Snapdragons are bushy plants with tall spikes of flower buds. Most are intensely colored and real standouts in the garden.
Leaves: The alternate, lanceolate leaves are arranged in a spiral around the stem.
Flowers: The flowers come in just about every shade, except true blue. Some are vibrant bold tones, some are soft pastels and some are subtly shaded bi-colors.
Caution: All parts of snapdragon are poisonous, if ingested.
Hardiness Zones:
Snapdragons are tender perennials that are only hardy to about USDA Hardiness Zones 8 or 9. In most areas they are commonly grown as annuals. Even when they do over-winter, they never seem to bloom as robustly as they did in their first year, which leads many people to think they are biennial, but they should form seed pods in their first year. If you're lucky, they may even self-sow.
Exposure:
They will bloom most profusely in full sun to partial shade, in the spring. Once the temperature heat up, they may stop blooming altogether. Planting them in partial shade and keeping them well watered will help them make it through the summer, to begin blooming again in fall. However they are quick to get established and it can be just as easy to replace your snapdragon plants each season.
Mature Size:
There are tall varieties and dwarf varieties and just about everything in between. Check the label or packet of the variety you are choosing.
Dwarf plants mature at a height of about 6 - 15 in. and from a dense, bushy plants with lots of flower stalks.
Tall varieties tend to be less bushy in habit, reaching a height of 30 - 48 in.
Some varieties bridge the two extremes, growing to a mid-sized 15-30 in. Of course, the actual size and fullness of the plants will also depend on growing conditions.
Bloom Period:
Snapdragons are at their best in cool weather. They can repeat bloom throughout the season, but do best in the cool of spring and fall and throughout the winter, in mild climates. Deadheading can increase the amount of buds that are set, but since the flower stalks begin blooming from the bottom up, they have a fairly long bloom duration anyway.
Suggested Varieties:
They're continually coming out with new snapdragon series. Most are sold as multi-color blends, but you can sometimes find individual colors in both seed and seedling. Some of the more popular series include:
- Arrow™ Formula Mix - Vivid colors on strong, branching stems. Grows 2' tall.
- La Bella Mix - A nice blend of colors from pale to bronze to deeply saturated. Grows 12 - 18" tall.
-
Rocket Mix - a dependable multi-colored series that grows to about 2 - 3' tall.
Design Suggestions:
Their spiky, bright colored flower stakes make a nice foil for the cooler shades of most spring flowers, like Brunnera and Bleeding Heart. Planted in clusters, they can help a border transition from the spring ephemerals to peak heat season.
The pale yellow varieties are the easiest to blend into a mixed border and work nicely with pinks, purples and even reds.
Breeders have been playing with snapdragons for a few years now and there are trailing and creeping varieties becoming more widely available. These are great filler plants for containers, baskets and tucked into walls.
Growing Tips:
Soil: Snapdragons like a neutral soil pH, between 6.2 and 7.0. As short-lived plants, they are not heavy feeders, but adding organic matter will help keep them healthy and blooming.
Planting:
Snapdragons can be winter sown, meaning you can toss the seeds out in late fall or even on top of snow, and most will germinate in the spring.
However snapdragons are most often either started indoors, 8 - 10 weeks before the last frost date, grown from cuttings or purchased as seedlings. When starting from seed, simply press the seed on the surface of the potting soil. Snapdragon seeds need light to germinate.
When seedlings have developed about 6 true leaves, pinch the top of the stem off, to encourage branching and a fuller plant. You can do this with purchased seedlings too.
Transplant snapdragons outdoors a couple of weeks before your last frost date. Snapdragons can handle a light frost or two.
Maintenance:
Regular deadheading will keep your snapdragons blooming longer. They won't need much care early in spring, but mulching to keep the soil cool and moist can help them handle summer better.
Snapdragons are tender perennials and may die off in colder climates. If they do survive the winter, prune them back by about 1/3, to encourage new growth. Don't be too disappointed if they don't last long. Snapdragons tend to go downhill after their first year and it's best to start fresh every year. Many varieties will self-seed and come back on their own, although they won't always look like the original plants you planted.
Some of the taller varieties will need staking.
Pests & Problems:
Snapdragons are affected by few pests or diseases. Rust and other fungal diseases can be a problem, especially in wet seasons. If you live in a damp or humid area, look for resistant varieties. Snapdragons may also attract aphids.
==========================================
金鱼草的栽培养护技术
http://www.ew9z.com/jinyucao-zaipei-yanghu.html
金 鱼草较耐寒，喜阳光，稍耐半阴，怕酷热，略耐干旱和微碱，喜欢肥沃、排水良好的土壤。在凉爽的环境中生长健壮。幼苗在5℃条件下通过春化阶段，开花适宜温度为15~16℃。以下介绍金鱼草的栽培养护方法及注意事项：
秋播的金鱼草于11月上旬定植于花坛或18~25厘米的花盆中。如果作花坛布置，栽植距离可依据品种的高矮而定，矮生种25~30厘米；中茎种30~40厘米；大花高茎种40~50厘米。
待真叶长出4~5片叶时要进行摘心，并移栽一次。作为切花栽培的大花高茎种和中茎种金鱼草不可摘心，但要及时抹去侧芽，以使单杆花枝独长，花穗又粗又长。在摘心后10天喷洒0.05%~0.1%的比九（B9）有显著的矮化效果。
除了在栽植前施足基肥外，应在生长期每2周左右追施液肥1次，但开花期应停止施肥。基肥可用骨粉、饼肥、腐叶土等腐熟的有机肥。注意干时浇水，雨后排涝，勤除杂草，促使植株长势旺盛。育苗期要注意间苗和保持土壤湿润，使苗生长健壮。
金鱼草较耐寒，也耐半荫，能抵抗-5℃以上的低温，-5℃以下则易被冻死。金鱼草耐湿，怕干旱，在养护管理过程中，浇水必须掌握“见干见湿”的原则，每隔2天左右浇水一次。每半个月施一次腐熟的饼肥水。由于金鱼草具有根瘤菌，本身具有固氮作用，因此只需适当增施磷、钾肥，而不需施氮肥。在花蕾出现后，用1%~2%磷酸二氢钾喷洒，可促使花繁叶茂。另外，随时剪去已经开过的花序，促使侧枝开花，延长花期。
也可对金鱼草进行促成栽培，冬春供花。办法是提前于夏末播种，先露地栽培养护，10月间上盆，天冷时移至室内阳光充足处，白天保持22℃，夜间室温在10℃以上，如肥水管理得当，可在元旦开花。
津京地区8月下旬秋播，当幼苗长出4~5片叶时移植摘心，小苗假植，冷床中越冬，盖上玻璃，夜晚覆盖蒲帘防寒，精心管理，于翌年春季5~6月开花。如在华东地区秋播露地越冬，4~5月开花。9月中旬播种于冷床越冬，翌年5月中旬进行摘心，6月下旬定植，7月初开花。
4月初于冷床春播的金鱼草，9~10月开花。7月中下旬对花谢后的植株，从植株基部剪掉所有枝条，并加强肥水管理，促进萌发新枝，可于“十一”国庆期间再度开花。温室栽培的金鱼草，可使其在冬春季节开花。
金鱼草的品种很多，若要区别花色和高矮品种，保持各品种的独有特性，采种母株应分地隔离栽植，以免相互杂交。种子也要分别采收，防止混杂。一般花谢后约20天左右种子成熟，当蒴果变为棕黄色时连同花梗一起剪下，晒干脱粒，贮存于干燥阴凉处。
