Merritt's Hydrangeas ‘Bloom 
Hydrangea Culture 
We are Hydrangea Specialists, growing no other Flowers 
or Plants. We do not force Hydrangeas into flower, but con- 
centrate all of our efforts to produce better Hydrangeas for 
you to bloom. We ship rooted cuttings and small plants, 
in season in all varieties, for growing on, and dormant 
Hydrangeas in the Fall and early Spring for forcing. We 
force some of every variety, each year, for a culture check, 
and they can be seen at our Greenhouses during the early 
Spring months. 
First, make sure of the varieties that grow best for you 
and that sell best in your locality. Try a few novelties each 
year to see how they act under your conditions, but stick to 
the proven varieties until you have found a better one. If in 
doubt, as to variety, please specify your selection early, mid- 
season or late, and we will give our very best judgment from 
our past experience giving the best varieties for your locality. 
If you propagate your own, do not make the common mis- 
take of rooting all of the blind shoots that appear. Remember 
that “Like begets Like” and if this practice is followed, it 
will eventually lead to disaster, and one day you will find a 
complete crop of blind Hydrangeas. Rather than that, keep 
varieties separate and select the very best flowering plants 
and get your cuttings from these by sacrificing the flower 
tips. It will pay dividends. 
The soil for potting should be low in nitrogen, particularly 
so with leafbuds, but should contain phosphorus, potash and 
calcium. A good mixture consists of two parts loam, one part 
of peat and one part of well rotted manure. If the original 
soil is very heavy, some sand may be added. Include a four- 
inch potful of superphosphate and a 24-inch potful of muriate 
of potash and the same amount of calcium sulphate (gyp- 
sum) to a wheelbarrow of soil. Complete fertilizers which 
contain nitrogen should be added later upon repotting. Keep 
the ph of the soil about 6:0. 
Shift the plants from two- or three-inch in which they 
were potted, directly into five- or six-inch pots and place these 
outdoors, after danger of frost, in the Spring. This is a 
better method than planting directly in beds. In regions of 
extreme heat, a lath house or a covering with snow fence is 
very desirable. Such half shade develops large foliage, par- 
ticularly if additions of ammonium sulphate are made about 
every two weeks, used as a liquid at the rate of one ounce to 
two gallons of water (three Ibs. to 100 gallons). During the 
same growing period two or three applications of such com- 
plete soluble fertilizer as 15-30-15 should be made using it 
at the above rate. This will insure adequate phosphorus and 
potash content. 
Depending on the color of the foliage, iron sulphate should 
be used to correct chlorosis. Use it at the rate of three pounds 
to 100 gallons or one ounce to two gallons. The iron will keep 
the foliage green. It has no bearing on the bluing of flowers 
unless the soil itself contains aluminum which may become 
available as the soil is acidified by iron sulphate. Growing 
in the field and not potting until September is a common 
method but its success depends on adequate rainfall, and 
only moderate heat in the summer. Usually under such a 
treatment most of the growth starts late, when temperatures 
are reduced and much blindless results. 
Pinching should be done from late June to mid-July, de- 
pending upon the locality and variety. The early pinching 
should be done in the north to produce enough growth before 
buds set in September. Pinch as low as possible, leaving two 
sets of leaves and thus four buds (where practical). If plants 
are well grown (properly fertilized and watered), the wood 
is sufficiently heavy and yet succulent so soft pinching is 
not objectionable. 
Depending again on locality, the plants under lath should 
be given full sun (by removing the snow fence) from August 
1 to September 1. The longer the plants are kept under lath 
the taller they get. The abrupt change from half shade to 
full sun may cause some foliage burn, but this is never 
serious if the plants are sprayed often with water. The 
change will cause the buds to set quickly due to the action 
of full light on the large foliage which will manufacture 
the food for the buds. 
An adequate watering system, or automatic water lines 
are your best insurance against drought. 
Earlier pinching is advocated when plants are grown with- 
out cover, particularly varieties like Strafford, Merveille and 
Dundalk. Sufficient growth must be produced by September 
to insure bud set. Pot grown plants are better than those 
planted directly in the fields or beds. Plunge them to reduce 
drying out, but be sure your soil drains well. 
During the growing period all weak shoots should be re- 
moved and the growth concentrated in the number of stems 
you wish to finish. It is best to do that as early after the 
buds develop from a pinch as possible. Again during this 
growing-on period don’t be stingy with water and fertilizer. 
Continue to give adequate water until October but be sure 
that your plants are in a protected frame or cool greenhouse 
before there is any danger of frost. Don’t take chances, even 
though well-hardened Hydrangeas will take a heavy freeze. 
The best place to store hydrangeas from about November 
on is a dark storage where the temperature may be kept 
between 35°-40° F. During this period keep the soil moist 
but don’t overwater. Drying out will shrivel buds. Be sure 
there is a proper circulation of air, to prevent bud drop. 
Spray or dust with ‘“Zerlate’”’ (DuPont) several times, while 
in storage. 
Start forcing right after your poinsettia benches have been 
cleaned out December 20 to 25th. Some advocate starting at 
50° F to 56° F. and then raising the temperature to 60° 
after about two weeks. Some people have difficulty in getting 
the plants to break quickly. This may be due to a number 
of causes. If you buy dormant stock, pot the plants in the 
same size pot as they were grown in. Repot when the new 
roots have started. Furthermore, don’t keep the plants so 
wet that there is not enough air in the soil to develop new 
roots from the dormant ball. If you are growing your own 
plants, again let us warn you about overwatering at first. 
There is a sensible limit to the suggestion of using lots of 
water. 
If you buy dormant plants and wish to save the double 
work of potting in the same size pots and later shifting to a 
large size, be sure that the soil you use is low in nitrogen, 
else you will have trouble. Likewise light crushing of the 
dormant ball will help the roots to develop more quickly. 
Add phosphorus, potash and calcium as indicated under 
soil for potting. 
To avoid yellowing of leaves (chlorosis), apply the iron 
sulphate and ammonium sulphate mixture as recommended 
previously. This is now during the forcing period. In addi- 
tion apply complete fertilizers (15-30-15 or similar) in liquid 
form two or three times during this period. Or use Electra, 
applied at the rate of a thimble full to a five-inch pot, every 
ten days during the forcing period, until the plants show 
color. Be sure the soil is moist (never dry) when applying 
fertilizer. To blue Hydrangeas, use aluminum sulphate at 
the rate of one pound to five gallons of water. Depending 
on your soil, 3-7 applications may be needed to give the 
color you want. Regular use of iron sulphate, especially 
where water is alkaline, will keep your blues cleaner. 
During the hot days of spring, do not permit plants to 
dry out or serious foliage burn will result. At the first sign 
of wilting, water and syringe. If you see signs of scorching 
due to drying and heat, syringe thoroughly and shade. Try 
to always give some ventilation, and as much as possible 
during the last days of forcing. If possible, reduce tempera- 
tures during the last two weeks before sale. You'll have 
better color and the plants will last longer in the house. 
- 60 buds should show, in most localities, six weeks before 
sale. 
For Mother’s Day, start forcing in February and follow 
the same general growing procedure. 
Keep red spider, thrips, aphids down with TEPP or 
Parathion aerosals. 
Mildew may be kept in check with Zerlate. 
Always remember, the best Hydrangeas come from the 
earliest cuttings, 
JOSEPH S. MERRITT 
