Fertilizing... Each year when flower stems and foliage begin to emerge from the ground in the spring, apply a treatment of a commercial fertilizer.
Watering...Like all flowers, bulbs appreciate regular watering. As a general rule, they should be deeply watered anytime natural rainfall is less than one inch per week during their growing and blooming season.
Mulching...A year-round mulch of compost, leafmold, leaves or commercial types of mulch has a positive effect on your bulbs and other flowers by keeping the soil from drying out, maintaining a more even soil temperature and reducing week growth. It also prevents soil from splashing onto the flowers and foliage.
After Blooming...Flowers should be removed when petals begin to fade, so they will not go to seed. If seed pods are allowed to remain, they will draw off the food needed to nourish your bulbs for next year's growth. All petals should be removed from the blooming area after they have fallen. Even where bulbs have been naturalized in a lawn, leaves should not be cut until they turn yellow and wither naturally. While they are still green, the leaves serve as a source of nourishment to the bulbs.
Natural Storage...Most bulbs prefer not to be disturbed and can be left in the ground for many years. But beware of overcrowding. When too many bulbs try to occupy the same space, they will be less vigorous and flowers will be fewer and smaller, an indication that it's time to transplant them.
You can dig up your bulbs as they are going dormant (which is when foliage is brown and papery and can easily be pulled free), divide and move them to a new location. Some varieties, of course, are more prone to multiply than others, and from time to time will need to be dug up and divided before being replanted at better spacing.
If you lift your spring-flowering bulbs after the foliage had died back, store them in a cool, dry place during the summer for replanting in the early fall.
Daffodils and the smaller bulbs - Crocus, Scillas, Grape Hyacinths, etc. - are better if left where they are so they can grow and multiply for many years. If they are planted at the proper depth, annuals may be planted right atop and amongst them.
Winter Protection for Hardy Bulbs and Perennials...It's a good idea to give your hardy bulbs and perennials some winter protection. You may want to mulch them lightly, especially the fist winter planting. Evergreen boughs, pine needles or leaves are ideal to use as mulch. This provides good protection in areas where there is alternate freezing and thawing, which may have a tendency to displace bulbs form their planted positions. Winter mulch should not be put down until the ground has frozen hard. Snow is a natural, and ideal final covering. Be sure to remove a winter mulch early in the spring, before your bulbs begin growing.
Lifting Tender Bulbs...Less hardy bulbs should be lifted each fall. As soon as frost has blackened foliage, gently spade up the bulbs, being careful not to cut into the bulbs and damage them.
If you prefer to lift the bulbs before frost had hit, you can dig your bulbs early and store them in a well-ventilated, frost-free area until they are dry. Just let the leaves remain on the bulbs until they become dry.
Most bulbs should be dried for about a week before you prepare them for storage. Then pull loose any remaining foliage, shake the bulbs gently to remove any clinging soil, dust them with fungicide powder to prevent rot and place them in unsealed paper bags or old nylon stockings with some dry peat moss to keep the bulbs from touching one another.
Dahlias should be dried for only a couple of hours before storing in plastic-lined shallow boxes with a blanket of vermiculite or peat moss.
Begonias should be given a bath just as soon as they are lifted and then stored in shallow, open trays. If there may be mice or other rodents, place a wire covering over the open trays.
Summer-blooming bulbs require a relatively low temperature for winter storage, 45-60˚ F (7-16˚ C). (Dahlias require an even lower temperature. If it gets above 45˚ F (7˚ C), they may sprout prematurely.) If you have space in the vegetable compartment of a refrigerator, it is ideal for bulb storage. Most modern basements aren't cool enough for winter bulb storage. Often an unheated garage is a good alternative. Make sure, however, that your bulbs will not freeze.
Bulbs, Corms, Tubes, Roots and Rhizomes... While we have referred to every summer-blooming flower from Holland as originating from a "bulb" many of the varieties described actually grow from corms, tubers, roots or rhizomes. While each is technically different, the instructions for care and planting apply uniformly.
Dutch Bulbs and Perennials require only a minimum of care during the summer blooming periods. Like all garden plants, they appreciate a weed-free growing area and watering when nature doesn't supply enough rain to keep the soil moist. Do not, however, let water stand around your bulbs - moist soil doesn't mean wet soil.
It generally isn't necessary to apply fertilizer while your summer bulbs and perennials are growing and blooming. Sometimes, however, you can increase blooming by adding dehydrated manure or another plant fertilizer. Be careful not to let any fertilizer touch the foliage.
In milder climate areas of America, where little or no frost can be expected, later planting is recommended. After receiving your bulbs from Holland, they should be given a "substitute winter" by pre-cooling them before planting. You can store them in opened packages in the bottom of your refrigerator. (Fruit should not be stored in the refrigerator while bulbs are cooling, since it produces gases which could damage the bulbs.) A six-to eight-week cooling period is recommended.