How to Grow Glads



The North American Gladiolus Council appreciates you purchasing corms from a North American cataloger. We hope you enjoy the pleasure of growing glads and will pass a few onto family and friends. Our goal is to assist people in purchasing and growing glads. We support glad shows and societies across America.


Most people start their adventure with glads purchased at a Garden Center. Since they are limited to shelf space they can carry only a few cultivars (varieties) or mixed bags. We are happy you have graduated to one of our many catalogers, where a world of thousands of cultivars are available. Upon receipt of your gladiolus order, if they are in paper bags, open each bag so they can air. Some catalogers may use mesh bags, which will naturally air. Place the open bag in the coolest, non-freezing location available, until you are ready to plant. Your corms (bulbs) are coming out of controlled storage (humidity and temperature) and will try to grow before planting if left packed in their shipping box. Your corms are ready to break dormancy and sprouts on the the top or root nodes on the bottom my be appearing, or soon will. If you also have decided to purchase corms from a Garden Center, purchase them early, when they first appear on the shelf. Store conditions are too warm and too dry for keeping corms in excellent condition. We discourage buying store corms when they go on sale later in the season, as the corms will deteriorate and we are afraid you will be disappointed in their performance. It is expensive and near impossible for catalogers to picture all the thousands of glads available. Most glads are sold by description and classification number. This is explained later in the booklet, under “Gladiolus Classification.”


We find that applying approximately one pound of 8-16-16 fertilizer per one hundred square feet will get your glads off to a good start. The rest can be applied to your vegetables or other flowers. Do not over fertilize glads. If you apply fertilizer with a heavy hand, it would be best to apply it in the Fall. Glads appreciate humus rich soil. Compost or peat moss can be worked into the soil in the Spring before corms are sown, if so desired. It is not recommended to compost glad tops because disease can be carried back into the soil with the composted material. Uncomposted animal manures or leaves should only be worked into the soil in the Fall. Plow, rototiller or spade your soil as you would for any other garden seed or plants. It is always best to move your glad planting from one side of the garden to the other each year, in case of disease carry over in the soil, especially if you don’t remove old plants. Even poorer soil can grow good glads, with a little soil preparation.


Start planting when you would normally plant your sweet corn, after the danger of a freeze. If you are in a location where it does not freeze and the summers are hot, plant the corms early so they bloom before intense heat. Plant a few corms every ten days. Planting in this fashion allows for blooms all season long. You cannot permit the corms to freeze, but a little frost will not kill the underground corms or glad shoots. Plant corms 3 to 5 inches deep and 4 to 12 inches apart. A little soil insecticide spread in the trench before covering, will discourage underground insects. Covering the corms with 2 inches of soil at planting time and later hilling in needed soil when glads are several inches above ground, permits glads to get a quicker start, especially in heavier soils. You can fill in the trench to the full depth at planting time, if you wish. Before glads bloom, hilling soil six inches up around the stalk helps prevent the glads from tipping over during storms. Glads love full sun, but will do reasonably well if the shade is early morning or late afternoon. Gladiolus should be planted away from bushes, buildings, or other obstructions that impede air flow and provide competition for their growth. Water drainage is even more important. While gladiolus like plenty of water, they will not tolerate wet feet. Glads may be planted in rock gardens if watered and fed, and surrounding plants do not compete for sunlight.


Shallow cultivation or a light layer of organic mulch, such as peat moss or straw between the rows, discourage weeds. Preen, sold at most Garden Centers, can be used on glads to help prevent weeds, without any ill effect to the glads. If you prefer, shallow cultivation throughout the season will control your weeds. This will also allow the soil to air, especially if you are in wetter locations. Although some gardeners do not spray their glad patch, we find that spraying with Malathion, Sevin or Orthene every ten days to three weeks as needed, will keep the bugs away that spread disease. Organic gardeners can use sticky traps and general organic methods that control insects on their other plants. (CAUTION-follow all chemical label directions.) Glads may be staked if in windy locations. Miniatures are a good buy for limited space gardens and are shorter, making them easier to care for and less apt to tip over.


Although many people do not dig their glads and just buy new stock each year, we find removing the old plants from the garden stops carryover of disease. Dig your gladiolus in September or early October, or around six weeks after your glads have bloomed. In warm locations, where the ground does not freeze, they may be left to bloom a second year, but we find digging them and replanting keeps them healthier and reduces crowding. Loosen the soil with a spade or digging fork and pull the plants by hand. Separate the plant from the corm as close to the corm as possible, either by hand or with pruning shears. Corms should be brought from the garden, rinsed off with running water and allowed to dry. Cure the corms in shallow layers or trays, in an airy spot, protected from direct (scorching) sun, where temperatures stay above freezing. At this time a corky layer will form between the new corm and the old mother corm and roots. It usually takes 10 to 14 days to separate easily. Break off and discard this old corm and roots, as soon as possible. It will be difficult to remove later. The tiny round cormels around the base of the large corm, can be saved and planted to increase your stock. They are identical clones of the mother corm. If planted early in the Spring, many of these cormels will produce larger corms and some will bloom in September. Store the corms with the husks intact (do not peel.) After cleaning, sprinkle the corms with a combination fungicide-insecticide corm dust, which can be purchased at your local Garden Center. Storing them in shallow trays or mesh bags in a room with good air circulation and temperatures between 38 and 48 degrees, is optimum. Usually this is the coldest, non-freezing section of your basement. Glads will tolerate up to 60 degree storage temperature, but lower is better.


If you would like to personally view some beautiful and unusual cultivars, attend a gladiolus show. All the shows are listed in the Spring issue of the North American Gladiolus Council Bulletin. There usually is no charge to show glads and prize money to win. Anyone can enter gladiolus shows. A novice class is usually provided for the first timers, and possibly even a youth class for the children. At the shows, there is always someone available to assist those entering for the first time. If you see a gladiolus you especially like at a show, write down the name and number listed on the entry tag, so you may purchase that corm in the future. Glads shown under a number only are seedlings that have not been introduced, and usually cannot be purchased yet.


If you would like to meet people who enjoy growing glads, join a local society. Societies are listed on our website at You may wish to join our national organization, the North American Gladiolus Council, where you can attend conventions and learn more about growing gladiolus. The Glad World, quarterly publication includes upcoming shows and societies. An application form is located on the back page. Any classification number ending in an odd digit (1,3,5,7,9) indicates “with conspicuous markings.” For example, while 66 means plain dark rose, 67 means a dark rose with markings. The first number (1 thru 5) indicates the size of the floret, with 1 being under 2-1/2 inches across, 2 being 2-1/2 to 3-1/2 inches, 3 being 3-1/2 to 4-1/2 inches, 4 being 4-1/2 to 5-1/2 inches and 5 being over 5-1/2 inches across. For example, the gladiolus name Gold Struck is classified as 416. It has a floret size of between 4-1/2 to 5-1/2 inches and is a dark yellow. Glad classifications starting with 1 and 2 are considered miniatures. For instance, the glad “Black Lash” is classified as a 268. It has a floret size of between 2 1/2 to 3 1/2 inches and is a black/rose. 3, 4 and 5’s are considered large flowered glads.


The following publications are available from Bud Bullard, NAGC Publication Director, 6595 Hitchingham Rd., Ypsilanti, MI 48197. “HOW TO GROW GLORIOUS GLADIOLUS” - A 160 page book; Back issues of “Glad World”, Classification Lists and the Buyers Guide.



Intensity Range

Pale Light Medium Dark Darkest
White 00        
Green   02 04 06  
Yellow 10 12 14 16  
Orange 20 22 24 26  
Salmon 30 32 34 36  
Pink 40 42 44 46  
Red 50 52 54 56 58 Black/Red
Rose 60 62 64 66 68 Black/Rose
Lavender 70 72 74 76 78 Purple
Violet 80 82 84 86  
Smoky 90 92 94 96

98 Brown


Receive four “Glad World” publications yearly. Dues are $20.00 annually. Publication includes listing of shows, winning cultivars reports, chemical and cultural updates, and Talk Radio, where you can ask any questions about glads, and much more....