When to plant the bulbs?
‘Flower bulbs’ is the generic term for plants that have a bulb, tuber, radical tuber or rootstock underground. Flower bulbs that will blossom in spring are planted in the autumn. Preferably between the end of September and December at the latest. The earlier they are planted, the sooner they will take root and develop sprouts. The ground will still be a little warm at the beginning of the autumn, so the bulbs will be better frost-resistant. With heavy frost, the ground can freeze up to 30 cm deep. Do not plant when the ground is already frozen or when it is too wet.
Soil and soil mixtures
Most important for good rooting and flowering of bulbous plants is undoubtedly an airy soil that is not too wet. In soil that is too wet the bulbs will choke and rot away completely. Flower bulbs will prosper best in light humus soil. Heavy clay-like soils can be attenuated with quite a big quantity of sand. Mix in a proportion of three parts sand to one part clay. Plow this mixture thoroughly by means of a flat-teethed fork or use a garden claw or cultivator. Make the soil friable, i.e. crush the big lumps till the soil is crumbly. The addition of a ready-made leaf mould would be excellent. Especially those bulbous plants that will remain in the ground – so will not be removed after flowering – demand this kind of soil preparation.
Bulbous plants particularly like calcium-rich soil. A fertilizer, N.P.K. in the proportion of 5.10.5, can be added. Or mix a substantial amount of compost or bone meal through the soil. An amount of fertilizer of app. 5-6 kg/10m2 or – when compost is used – an amount of 20-25 kg/10m2 will be sufficient.
Where to plant the bulbs
All bulbous plants like a sunny to half-shadowed location. Crocuses and the many botanical tulips should be planted preferably in a sunny place. Apart from that, there are many bulbous plants that can be planted in a rather shadowy spot. Amongst others, these are the grape hyacinths (Muscari), anemone (Anemone nemorosa), ramson (Allium ursinum), hollow root (Corydalis cava), fumewort (Corydalis solida), yellow fumewort (Corydalis lutea), drooping star of Bethlehem (Ornithogalum nutans), spring snowflake (Leucojum vernum). Bluebell (Scilla nonscripta), summer snowflake (Leucojum aestivum), snow-drop (Galanthus nivalis), Solomon’s seal (Polygonatum multiflorum), and Snake’s head (Fritillaria meleagris).
Marking clearly – with sticks or anything similar – prevents damage when there is something that needs to be dug or raked nearby. For perennial plantings, it is best to keep a sketch of where the bulbs are planted, so that in summer, when the leaves have died and disappeared, there will not be any damage when other vegetation is planted.
Planting distance and Florescence
Given that most flower bulbs are packed and sold in garden centers and warehouses, it is usually mentioned on the package at which distance each of the bulbs can be planted. For an eye-catching effect during blooming the bulbs should be planted as close as possible. Also, keep an eye on the height of the different flowers, the taller ones should not hide the lower ones from view.
With the right choice of different flowering periods, you can have a succession of flowering bulbous plants and a wealth of colors.
Tulips for instance can be divided by variety for what concerns their florescence: Early tulips are a.o. the single-end double early tulips, the Greigii- and the Kaufmanniana-hybrids. The low-remaining kinds from these varieties are suitable as well for pots. Middle term flowering tulips are amongst others the Triumph- and Mendel tulips and the so-called Darwin hybrids. Late tulips are i.e. the parakeet tulip and the Liliaceae- or parrot tulip, the Rembrandt tulip, and the double late tulip.
Furthermore, there is quite a big collection of botanical tulips available. These tulips can remain in their place and can be planted in big groups, for example, on a lawn, on a wide border, or at the foot of a hedge. Suitable varieties are a.o. Tulipa turkestanica of which the flowering starts in early March (height 20 cm). This variety is multi-floral and flowers in a remarkable creamy color. The Tulipa kolpakowskiana flowers are yellow-red in April (height 15 cm), while Tulipa marjolettii flowers in May in are red-white and become 50 cm high.
How to plant? How deep?
The soil should be well prepared before the bulbs can actually be planted. After preparing the soil will have a loose and airy structure. That is why pricking with a pointed tool is absolutely unsuitable; the air pocket down in the planting hole prevents in this case that the bottom side of the bulb can get in touch with the soil. It is better to use a special bulb planter. The bulb planters can be found in two types: a planter that needs to be emptied by knocking the soil out and a planter with a kind of spring that pushes the soil out automatically. Especially when a lot of bulbs need to be planted it is recommendable to invest in the latter type. Of course, one can also use a simple small spade but the disadvantage of a spade is that the bulbs are not all planted at the same depth. So there will be differences in the height of the flowers and even some bulbs will not flower at all! When planting big sections, the use of a flat shovel can be very useful and for big sections of planting, if planting in lawns, it is a must. This Dutch way of planting is also very useful when the bulbs do not need to be planted in perfect order but spread over a big surface. By dissemination, it will give a more ‘natural’ view. Especially for botanical bulbous plants, this will give a very nice appearance.
As a rule, the depth of the planting hole equals three times the maximum diameter of the bulb. There are however so many exceptions to the rule, that it is better to determine beforehand which depth counts for the bulb that was purchased. The planting depth is always related to the distance between the bulb nose and the top of the soil after covering the bulb.
Planting bulbs in a box or a pot on the balcony
To enjoy the floral splendor of bulbous plants, you do not need a garden. A couple of big pots of 25-30 cm tulips, narcissus, snowdrops, or crocuses can still give you the “spring feeling”. Make sure to use a bigger pot for this purpose. Make sure the pot can drain well. Cover the bottom of the pot with potsherds or pieces of polystyrene. Then cover this with a layer of sand and on top a good potting soil. Planting can be done in different layers! If you choose varieties with different flowering periods and heights, you can enjoy this mini-garden for a long time. Combinations of daffodils and grape hyacinths for example are very well possible. With heavy, continuing frost the pots should be protected. Covering with straw or gunny is effective.
Suitable varieties for pots or flower boxes are:
Crocuses: Crocus laevigatus, Crocus ancyrensis, Crocus chrysanthus, Crocus tommassianus and all their culture varieties Crocus flavus.
Daffodils: ‘Baby Moon’, ‘Tête-à-Tête’, Narcissus campernelli, Narcissus nanus, Narcissus pumila, Narcissus canaliculatus, Narcissus asturiensis.
Tulips: ‘Apricot Beauty’, ‘General De Wet’, ‘Beauty of Volendam’ , ‘Van der Neer’, ‘Diana’, ‘Stockholm’, ‘Carlton’, ‘Estella Rijnveld’, ‘Bonanza’ , T. praestans ‘Fuselier’, T. praestans ‘Brilliant Star’, ‘Joffre’, ‘Christmas Marvel’, ‘Unicum’, ‘Fringed Beauty’, ‘Heart’s Delight’, ‘The First’, ‘Early Harvest’, ‘Goudstuk’, ‘Johan Strauss’, ‘Gluck’, ‘Jeantine’, ‘Berlioz’, ‘Treasure’, “Mary Ann’, T. bakeri ‘Lilac Wonder’, T. batalinii etc.
You will be able to find many more varieties that are not too high and will therefore be suitable to plant in pots and boxes. For exceptional bulbous plants that can be planted on the balcony as well, we refer to the next point.
Bringing forward bulbous plants for room cultivation
In principle, there are three ways to cultivate bulbs for room cultivation.
There are 3 ways to do so: a. on water, b. on gravel, c. in potting soil.
- On Water: Use special glass vases for hyacinths, tulips, or daffodils or special plastic jars with a lid, in which the bulbs can be clasped. For the best result, you should buy specially prepared bulbs. These bulbs are “pretreated”, which means they have been exposed to the cold (cold store) for a certain period. During this cooling period, the so-called receptacle (primordium) is formed. This method is called “vernalization”. You can do this yourself. Put the bulbs you bought (untreated) in a plastic bag with holes, so the bulbs can ‘breathe’. Store these bulbs for 4-6 weeks in the vegetable drawer of the fridge at a temperature of 5-6 degrees Celcius. Make sure they do not freeze!
For Amaryllis and daffodil ‘Tazetta’ this treatment is fundamentally wrong. Put the bulb (bought treated or treated yourself) in the glass filled with water. The bulb should be stuck to avoid it will keeling over later. Place the glass/jar with the bulb in a dark, cool spot. The maximum temperature should not rise above 12 degrees celcius. A dark closet in an unheated bedroom or a dark place in a basement shed or garage will do. After 3-4 weeks a sprout of about 5-6 cm is formed, then the bulb can be placed in a heated room. You have to pay attention to see if there is enough water in the glass or jar during the whole period. The water should stay approximately 1/4 inch under the bottom part of the bulb. Varieties suitable for glass/jar culture are:
Hyacinthus ‘Pink Pearl’, ‘Carnegie’, ‘Delft Blue’, and ‘Ostara’, Narcissus ‘Tazetta’, ‘Cragford’, ‘Grand Soleil d’Or’, Crocus ‘Remembrance’, ‘Zwanenburg Bronze’, ‘Skyline’, ‘Jeanne d’Arc’, ‘Vanguard’, ‘Grote Gele’. Tulips: ‘Brilliant Star’, ‘Joffre’, ‘Christmas Marvel’, ‘Prominence’, ‘Flair’, ‘Electra’, ‘Peach Blossom’, ‘Mr. van der Hoef’etc.
- On Gravel: The culture or planting method, the necessary treatment of the bulbs equals the one for water cultivation. The gravel actually replaces the planting soil. Use a waterproof pot. The material of the pot does not matter. Put at least 2-5 inches of gravel in the pot. Fill it up with water and make sure that when the bulbs are planted, the bottom of the bulb is not underwater. Fill up regularly with water as long as the bulbs are ‘pulling’. Further treatment is the same as that of bulbs on water. Suitable varieties for gravel culture are: Narcissus ‘Totus albus’, ‘Paperwhite’, Narcissus ‘Grand Soleil d’Or’, N ‘Tazetta’. Muscari (grape hyacinth); Armeniacum ‘Cantab’, ‘Blue Spike’, ‘Heavenly Blue’, Muscari botryoides ‘Album’, Muscari tubergenianum, Muscari comosum plumosum.
- In Potting Soil: Choose a light and airy potting soil. The soil should be water permeable, so mixing the soil with 1/3 of sand is very good. Do not mull the garden soil. All pots of a good size are very suitable. Put some gravel or potsherds on the bottom for drainage. Then the soil mixture can be put directly on top. Fill up the pot with soil till 1/2 inch under the edge because of watering. Put the pots in a cool place; the temperature should not be higher than 10-12 degrees celcius.
Check regularly whether the bulbs are not eaten away by mice! It is not necessary to put the pots in a dark place. Another possibility is to dig the pots in the garden. Dig a hole so that the top of the pot stays a maximum of 10 inches below the surface. Mark the place where you dug in the pot and cover it with a layer of straw, sawdust, or clean sand. This simplifies digging out, after the frost. After about eight weeks everything can be dug out again. In case you do not have a garden, the pots can be covered with black plastic foil. By bringing the pots inside at different intervals you can extend the period of blossoming flowers in the house.
Try planting something different from tulips, daffodils or crocuses!
There is much more to accomplish in the garden beside the most common bulbous plants. The flowering season can last until even the end of June with the help of bulbous and tuberous plants.
In the 17th century (1630 – app. 1637) a rather bizarre tulip mania, also called “tulip rage” or “tulip craze” arose in the republic of the Seven United Netherlands: suddenly tulip bulbs became speculative merchandise.
This rage drove the prices up to excessive heights, even up to the point when a bulb was worth its weight in gold. The rage was at its peak at the end of 1636, until the beginning of 1637. In February 1637 the “bulb market” collapsed just as suddenly as it had developed; many speculators were left with nothing.