The Hawkweeds, or Paintbrushes. 7 
exercised to see that all the below-ground growth is removed, since 
even a small piece if left in the soil may develop into a new plant. 
Such underground growth usually extends a distance of 8 inches 
beyond the aboveground limit of the patches. The exposed soil 
marking the spots where the hawkweed formerly grew should then 
be heavily seeded with the best grass mixture obtainable. Constant 
vigilance is needed thereafter in order to prevent the seeding of any 
hawkweed which may have been overlooked, since the seeds are blown 
by the wind and a single plant may be the means of infesting large 
areas. The inspection of the farm for stray patches of hawkweed 
is best done from horseback when the plants are in flower, since they 
are then most readily seen. 
Another method of eradicating small scattered patches of hawk- 
weeds is to cover them with tarred or some other type of heavy paper, 
to the complete exclusion of light. The paper should be pegged to 
the ground or weighted down with stones and should cover the patches 
for an entire season. ‘This method is expensive when the number of 
patches to be treated is large, but complete eradication is practically 
certain if the infested areas are well covered. 
CULTIVATION. 
Where the area of infestation is large, the hawkweeds may be 
driven out by placing the land in intertilled crops, such as corn. 
IMPROVING THE TURF. 
Top-dressing with manure or commercial fertilizer will tend to 
produce a more luxuriant growth of grass, with which the hawkweeds 
will have less chance to compete successfully. Do not harrow such 
grasslands, since harrowing merely serves to spread the weed. 
SPRAYING. 
Spraying with a saturated salt solution and with other chemicals 
has been attempted, but dry salting is simpler and better; hence the 
use of sprays is not recommended. Spraying at best is a hard, 
tedious, and expensive procedure. 
PRECAUTIONARY MEASURES. 
In large areas of infestation where eradication methods are not 
attempted, the hawkweeds should be mowed twice a year at the time 
when the flower heads first appear, usually in June and August. The 
main purpose of mowing is to prevent the maturing of seeds, since 
seeds are readily scattered by the wind to adjacent fields. 
Preventive measures are extremely important when hawkweed is 
first discovered. All plants found should be destroyed immediately 
and their location marked. Frequent inspection should be made 
thereafter in order to make sure that the weeds do not reappear. 
